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newsEA
WA
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59e November 2005Swiss Federal Institute for Environmental Science and Technology (EAWAG), A Research Institute of the ETH-Domain • CH-8600 Dübendorf
EAWAG
Agriculture and Water Quality
Use of Antibiotics in Agriculture – Consequences for the Environment 12
Pesticides: Risks to Lakes and Streams? 20
Contaminated Drinking Water from Agricultural Areas? 9
Agrochemicals – How Dangerous are They for Lakes and Rivers? 3
Stephan Müller, Head of theWater Protection Department,FOEFL (till April 2004 head ofEAWAG’s Water and AgricultureDepartment).
EAWAG news 59 2
EditorialWater Protection and Agricultural Policy
Sitting in the Same Boat
EAWAG news 59e • Nov. 2005Information Bulletin of the EAWAG
Publisher Distribution and © by: EAWAG, P.O. Box 611, CH-8600 DübendorfPhone +41 (0)44 823 55 11Fax +41 (0)44 823 53 75http://www.eawag.ch
Editor Martina Bauchrowitz, EAWAG
Translations EnviroText, Zurich
Linguistic revision Helen Brügger-Clarke, Zurich
Figures Peter Nadler, Küsnacht
Copyright Reproduction possible on request. Please contact the editor.
Publication 2–3 times per year in English, German andFrench. Chinese edition in cooperation with INFOTERRAChina National Focal Point.
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ISSN 1440-5289
EAWAG
Agriculture and Water Quality2 Editorial: Water Protection and Agri-
cultural Policy Sitting in the Same Boat
Lead Article3 Agrochemicals – How Dangerous are
They for Lakes and Rivers?
Research Reports6 Agricultural Policy and Water Protection
9 Contaminated Drinking Water fromAgricultural Areas?
12 Use of Antibiotics in Agriculture –Consequences for the Environment
16 Pesticides in Water – Research Meets Politics
20 Pesticides: Risks to Lakes andStreams?
24 Promoting Location Suitable Land Use
27 National Strategy for AgriculturalNitrogen Reduction
Forum30 In the conflicting area of agriculture
and water protection
In Brief31 Publications
32 In Brief
When we think about summer, we think
about bathing in our lakes and rivers, swim-
ming from one bank to the other, or navigat-
ing gently down the Rhine in a rubber
dinghy. From Stein am Rhein to Schaffhau-
sen, for instance – one of the most beautiful
river landscapes in Europe. We pass railway
bridges, dense forests, camping places and
everywhere open, rural areas. Agriculture is
one of the dominant uses of land in Switzer-
land – and its role in water protection is
decisive.
Important measures in the agricultural field
influencing the improvement of the water
conditions were the linking of the direct
payment schemes to the Proof for Eco-
logical Performance (PEP), and the intro-
duction of Article 62a in the Water Protec-
tion Ordinance, which created the basis for
financing the remediation of contaminated
water bodies. Although the European Union
is currently developing its agricultural poli-
cies in a similar direction, these laws place
Switzerland in the vanguard of water protec-
tion in Europe.
Now, after more than a decade, how is the
agricultural policy faring? Most of the contri-
butions in this edition of EAWAG news are
in answer to this question. Good results
have been achieved in the reduction of
nitrate levels in groundwater. Since the
mid-90s, impacts have been significantly
reduced in two-thirds of the tested sites.
Progress has also been made in an other
classical problem area – the phosphate
emissions to Swiss lakes. Some large lakes
are still too heavily contaminated. In addi-
tion, the accumulation of phosphorus in
soil due to excessive fertilization is a reality
and will lead to increasing impacts in the
lakes.
The management of the approximately 400
pesticides approved for use in Switzerland
leaves much to be desired. The pesticide
concentrations measured in small and
medium-sized watercourses in many places
exceed the legal limit of 0.1 µg/l, laid down
by the Water Protection Ordinance, as well
as scientifically determined quality values.
Furthermore, the BUWAL groundwater mon-
itoring program has detected traces of pes-
ticides in 60% of the ground water. A more
consistent protection of surface waters and
ground water is therefore absolutely essen-
tial.
In order to reduce the impacts on water
bodies from agriculture further, the Direct
Payments Ordinance and/or the provisions
of the PEP must be adapted accordingly.
The implementation of the WTO agreement
means that market support funding will be
replaced by direct payments, which provide
the best mechanism for water quality pro-
tection. Recent evaluations developed on
the basis of site-specific features demon-
strate that this is possible without raising the
economic burden.
Meanwhile, we arrive with our boat at the
city of Schaffhausen. Does our water pro-
tection and agricultural policy journey end
here? Or can we pass the Rhine Falls over-
land and use the time for effective and con-
structive discussion of the new Agricultural
Policy 2011? Refreshed with new ideas on
board, we can take to the water again be-
low the Falls and swiftly solve the pressing
problems.
3 EAWAG news 59
Agriculture relies on large quantities of agrochemicals. Rain trans-fers at least a portion of these chemicals into lakes and rivers.Therefore, agriculture and water protection seem to be at odds.However, the state is making enormous efforts to improve thesituation and is financing measures to prevent agrochemicals fromreaching the waterbodies. The various articles contributing to thisvolume highlight how large the impacts are, whether the measuresimplemented actually work, and how the total package of meas-ures may be advanced best to meet the future challenges.
Switzerland is no longer an agricultural
country. This conclusion might be drawn
in view of the gross national product ac-
quired by the agricultural sector. Currently,
it contributes just 0.8% to the total (Fig. 1).
Does this mean that agriculture is no longer
a subject for water protection?
The answer is a clear “No”, since agriculture
is still one of the dominant land uses in
Switzerland. Around 40% of the total pre-
cipitation flows through agricultural land
(including alps). Large amounts of nutrients
and other agrochemicals are used on this
land, and a considerable proportion of these
agrochemicals will be transported with the
rain into surface and ground waters (see
box). The quality of a majority of our water
resources is therefore directly dependent on
how well agricultural activities are managed
(Fig. 1).
At the end of the 1980s, the problems result-
ing from the use of agrochemicals could no
longer be overlooked: excessive concentra-
tions of phosphorus in lakes, nitrate con-
tamination of drinking water, and pesticide
pollution of surface waters, are just the
worst examples. The policymakers had to
respond (see article by Conrad Widmer on
p. 6). Since 1993, there has been a new ori-
entation in Swiss agricultural policy. Direct
payments by the state have encouraged
production forms which are particularly
benign for the environment and for animal
welfare. Furthermore, since Article 62a was
implemented into the Swiss Water Protec-
tion Ordinance in 1998, it has been possible
to remediate contaminated waterbodies
through regional projects with the help of
financial incentives to farmers.
Optimizing Nutrient CyclesAlthough the number of nutrients used in
agriculture (see box) is relatively small, the
applied quantities are large. This is particu-
larly the case for nitrogen, phosphorus and
potassium. Thousands of tonnes of these
major nutrients are spread on Swiss agricul-
tural land every year: in 1995 1.6 x 105 t ni-
trogen, 2.0 x 104 t phosphorus, and 5 x 104 t
potassium [2]. Nutrients are mainly applied
onto the agricultural soils in the form of
solid and liquid farm manure. Compared to
the total nutrient cycle on the farms, addi-
tional commercial fertilizers and feeding
stuff make up only a relatively small propor-
tion: in 1995 these amounted to only 18%
for potassium, 28% for nitrogen, and 42%
for phosphorus. Ideally, there would be a
nutrient cycle to which only nutrients assim-
ilated by the harvested products are added
in the form of fertilizer. Correspondingly, the
nutrient cycles must be optimized, to mini-
mize the impact of nutrients on waterbod-
ies. The report by Werner Hediger on p. 27
investigates whether the nitrogen cycle has
in fact been optimized by the new agri-
cultural policy since the introduction of the
direct payments scheme.
Minimizing Use and Losses of Auxiliary AgentsThe situation is different for the auxiliary
agents applied in agricultural production.
Currently, around 400 pesticides and 1150
animal medicaments are licensed in Switz-
erland. Since these substances are biologi-
cally very active, the amounts used are quite
small: around 35 t of veterinary antibiotics
AgrochemicalsAgrochemicals are all chemicals used in agriculture. These include nutrients and auxiliaryagents. There are five main nutrients (nitrogen, phosphorus, potassium, sulphur, and magne-sium) and about 10 micro elements (e.g. iron and cobalt). Auxiliary agents include mainly pesti-cides and veterinary pharmaceuticals, but also silage additives to extend the storage time offorage, substances acting as stalk shorteners, and lime to improve soil quality.
The application mode of the various auxiliary agents – and thus their input into the environment– differs greatly. Pesticides, for example, are sprayed directly onto the fields, whereas veterinarysubstances such as antibiotics arrive indirectly on the fields through animal excrements, e.g.,liquid and solid farm manure.
In addition to the agrochemicals, other environmentally harmful substances can enter the envi-ronment through agricultural activities. Heavy metals, for instance, are such problematic sub-stances. They are often contaminants of mineralized fertilizers, compost and sewage sludge. Assewage sludge, in addition, contains other harmful substances besides heavy metals, its use asfertilizer has been restrained in Switzerland since 2003, and will be totally banned as of 2006.
Per
cent
80
70
60
50
40
30
20
10
0Employees Gross
nationalproduct
Runoff Nitrate
Fig. 1: Agricultural proportion of total employees, ofthe gross national product [1], as well as of the agri-cultural influence on runoff formation and on nitratepollution of ground waters.
Agrochemicals – How Dangerous areThey for Lakes and Rivers?
EAWAG news 59 4
(year 2001) and about 1.5 x 103 t of pesti-
cides (2003) are sold annually in Switzer-
land. Auxiliary agents are used in one-off
doses and there is no substance cycle. The
problem is that most of the auxiliary agents
do not just disappear from the environ-
ment; instead they are translocated and
may reach surface and ground waters where
they can have undesirable effects. For aux-
iliary agents, emphasis is therefore placed
on measures minimizing both their usage
and their loss to the environment. In his
article on p. 16, Heinz Singer estimates
whether the pesticide pollution of water-
bodies was actually reduced by half as
targeted by the Swiss policy.
Induced ImpactIt is often forgotten that agricultural activi-
ties can also lead to water pollution that is
not directly traceable to the external input
of substances. This may be referred to as
induced impact. A major induced impact is
erosion, which carries soil particles into the
water. Eroded soil particles may carry with
them nutrients and auxiliary agricultural
agents.
Agricultural operations may also cause an-
other induced impact, the pollution with
undesirable microorganisms. Microorgan-
isms such as cryptosporidia and antibiotic
resistant bacteria can enter the environment
directly through the excrement of grazing
animals, or indirectly through the applica-
tion of excrements from housed animals.
Whether Cryptosporidium species patho-
genic to humans presents a hazard for
drinking water, is the subject of the article by
Hans Peter Füchslin on p. 9. Krispin Stoob
(p. 12) examines the environmental fate of
veterinary antibiotics, and whether the de-
velopment and spread of antibiotic resistant
bacteria is promoted by the use of antibi-
otics in agriculture.
Differing Input Dynamics of AgrochemicalsSurface and ground waters are contaminat-
ed by agrochemicals that are transported
with the rain from the soil to the waterbod-
ies. Due to their different input dynamics, we
may broadly distinguish two groups of sub-
stances: in one group, the concentrations in
small streams increase due to a runoff event
(Fig. 2A), while in the other group a dilution
effect is observed (Fig. 2B). Phosphorus,
pesticides or microbial pollutants belong
to the first group. High concentrations of
these compounds are generally restricted
to the upper soil layer. Only when they are
removed by rapid transport processes with
the rain (surface runoff, macropore flow),
do higher concentration levels occur in the
waterbody.
Nitrogen in the form of nitrate belongs to the
second group. It does not sorb to the soil.
Instead, it is dissolved in the soil pore water
and thus continuously reaches surface and
ground waters. If nitrate is applied in ex-
cess to crop needs and is not converted
by microbial processes (denitrification), the
nitrate concentration in the neighboring
waterbodies is high. During rain events,
the nitrate concentration can, therefore, be
diluted. For an evaluation program, knowl-
edge of the various runoff and input dy-
namics is essential, so that the appropriate
timing for sampling can be properly estab-
lished.
Most agrochemicals are retained by the soil
through sorption, and will be biologically
and chemically transformed during time. In
this way, the soil acts as a highly efficient
filtering system for the waterbodies. This is
evident from the quantities of agrochemi-
cals entering the waterbodies which are at
most a few percent of the total quantities
used (Fig. 3).
Discrepancy between Agri-culture and Water ProtectionThe fact that agriculture comes into conflict
with water protection – despite the rela-
tively low emissions – is a consequence of
the differing effect of the substances on
agricultural and aquatic ecosystems. Con-
cerning nutrients, agricultural ecosystems
and waterbodies ideally should have a dif-
ferent trophic status. A high agricultural
production is only achieved on nutrient-rich
soils. Healthy aquatic ecosystems on the
other hand should be nutrient-poor. This
means that e.g. the phosphorus contents
should be one to two orders of magnitude
different: typical phosphorus concentra-
tions of fertilized topsoil range between
300 and 1000 mg per m3 pore water, where-
as those of surface waters should not ex-
ceed 30 mg per m3 water.
The underlying ideas concerning the use of
auxiliary agents are completely different
with regard to their respective effects on
agricultural ecosystems and on waterbod-
ies. Herbicides for example should com-
pletely remove weeds on fields. Corre-
Run
off (
m3 /
s)
2.0
1.5
1.0
0.5
0
Pho
spho
rus
(µg/
l)
800
600
400
200
050403020100
Time (hours)60
Run
off (
m3 /
s)
2.0
1.5
1.0
0.5
0
Nitr
ate
(mg/
l)
8
6
4
2
050403020100
Time (hours)60
A
B
Fig. 2: Concentration dynamics of (A) phosphorus and (B) nitrate (black curves) and runoff (blue curves)during a rain event in a small agricultural catchmentarea (Kleine Aa at Lake Sempach in the canton ofLucerne) [3]. Pesticides, heavy metals and sedimentsusually show dynamics similar to phosphorus.
Extraction of a soil sample.
Pho
togr
aphs
: E
AW
AG
Christian Stamm, biologist andsoil scientist, is head of thegroup Water and Agriculture inthe Department of Environ-mental Chemistry. He has beenstudying the transport of agro-chemicals from agricultural soilsinto waterbodies for years, and
is investigating possible measures for reducing thederived impacts
5 EAWAG news 59
spondingly, this requires a high dosage. In
contrast, the herbicide concentration in the
water should be very low as to exclude the
damage of aquatic organisms.
Evaluating Water PollutionAfter decades of research, we are able to
formulate scientifically-based quality targets
(threshold values) for the nutrient pollution
of waterbodies today. This is, however, not
the case for other agrochemicals. The defi-
nition of scientifically-based quality targets
for pesticides and pharmaceuticals is cur-
rently an important subject of research. This
is mostly due to the fact that the two main
nutrients, nitrogen and phosphorus, fulfill
the same vital and well-known metabolic
functions in basically all organisms, while
auxiliary agents such as pesticides act
differently on different organism groups. In
order to deal with these variable impacts
appropriately, we need conceptual guide-
lines along with specific analytical methods.
Nathalie Chèvre presents in her article on
p. 20 a new method that allows the defini-
tion of sound effect-based quality targets
for individual pesticides and pesticide mix-
tures.
[1] Bundesamt für Landwirtschaft (2003): Agrarbericht
2003. Bern, 288 S.
[2] Spiess E. (1999): Nährstoffbilanz der schweizerischen
Landwirtschaft für die Jahre 1975 bis 1995. Schriften-
reihe FAL Zürich-Reckenholz, Vol 28, 46 S.
[3] Gächter R., Mares A., Stamm C., Kunze U., Blum J.
(1996): Dünger düngt Sempachersee. Agrarforschung
3, 329–332.
[4] Braun M., Hurni P., Spiess E. (1994): Phosphor- und
Stickstoffüberschüsse in der Landwirtschaft und Para-
landwirtschaft. Schriftenreihe FAC Liebefeld, Vol. 18,
70 S.
[5] Leu C., Singer H., Stamm C., Müller S., Schwarzen-
bach R. (2004): Variability of herbicide losses from
13 fields to surface water within a small catchment
after a controlled herbicide application. Environmental
Science and Technology 38, 3835–3841.
[6] Stamm C., Singer H., Szerencsits E., Zgraggen K.,
Flury C. (2004): Standort und Herbizideinsatz aus
Sicht des Gewässerschutzes. Agrarforschung 11,
428–433.
Measures, Evaluation andPoliciesToday’s multifunctional agriculture should
not only take into account food production,
but also the protection of natural resources,
landscape conservation and the decentral-
ized settlement of the rural landscape [1].
Since these services are of public interest,
they are funded by the state through direct
payments. Hence the public authorities wish
to ensure that the desired public services
are really provided. In order to monitor the
success of the measures, clear (environ-
mental) targets have been defined, which
should be achieved by the year 2005. In
terms of water protection, the reduction of
nutrient and pesticide inputs into water-
bodies is a major aim.
It is not easy to evaluate the effectiveness
of the imposed measures. Factors such as
the complexity and the delayed reaction of
ecosystems to pollutants may hamper the
identification of impacts within legislative
periods. For this reason, it is important both
to register the change in the loads of pollu-
tants in the waterbodies and to acquire a
comprehensive understanding of ecosys-
tems.
Such a broad knowledge is necessary if the
catalogue of measure is to be advanced. In
the field of biodiversity, for example, it has
become apparent that the targeted 7%
of ecological compensation areas are not
sufficient to achieve the desired biodiver-
sity. As a result, and with an understanding
of the causes for the lack of success, the
catalogue of measure has been subse-
quently expanded.
In a similar way, our investigations have
shown that water pollution by herbicides
can probably be greatly reduced if the land
use is appropriate to site-specific condi-
tions [5, 6]. This conclusion is also drawn
by Christian Flury and Kurt Zgraggen, who
have combined the issue of site-specifity
with an economic analysis (see article on
p. 24). Their predictions calculated with an
economical land use model illustrate that
the intensity of agriculture and consequent-
ly the water problems resulting from agricul-
tural activities may develop very differently
depending on the governing political and
economic conditions.
Loss
es (%
)
25
20
15
10
0Atrazine Phosphorus Nitrogen
5
Fig. 3: Estimates of substance loss from agricultureinto Swiss waterbodies. The losses refer to the quan-tities of the substances which are added to agricul-tural soils (incl. N fixation for nitrogen). The valuesgive orders of magnitude based on investigations ofthe pesticide atrazine in the Greifensee (see article byHeinz Singer on p. 16) and the national phosphorusand nitrogen balances [4].
Soil profile with instruments to measure the soil water content.
EAWAG news 59 6
Agricultural Policy and Water Protection
Switzerland has a leading role in Europe with the reform to itsagricultural policy, and in particular with the Proof for EcologicalPerformance as prerequisite for direct payments. The area-widemeasures within the Proof for Ecological Performance meanwhilehave positive effects on water quality. Focus points for furtherimprovements to water quality include providing more space towatercourses and reducing local phosphorus excesses in soil.
Increased food self-supply to avoid short-
ages in times of war and crisis was the aim
of Swiss agricultural policy in the postwar
period till the end of the 1980s. This was
a continuation of the “Wahlen Plan”, pro-
posed by federal minister Friedrich Traugott
Wahlen during the Second World War, to
guarantee the Swiss population with a reli-
able food supply. Instruments of this policy
included fixed prices and supply guarantee
for important agricultural products. The
Swiss confederation intervened with thresh-
old prices for imported produce, customs
duties, quotas and cost covering acquisition
of excesses. By the end of the 1980s, this
policy was reaching its limits: costs were
increasingly burdening the federal budget,
consumer tourism abroad was rising, and
efforts to liberalize world trade as part of the
GATT agreement (General Agreement on
Tariffs and Trade) and the later WTO (World
Trade Organization) considerably increased
the pressure to bring down the protectionist
measures which were favoring Swiss agri-
culture. In addition, the environmental def-
icits of agriculture were becoming more
evident. Agriculture-derived phosphorus in-
puts in inland lakes were resulting in exces-
sive algae growth and severe oxygen de-
pletion – some lakes had to be artificially
aerated to sustain life – and in many drink-
ing water reservoirs nitrate levels were rising
alarmingly.
Reorientation from 1993In the Seventh Agricultural Report in 1992
[1], the Swiss Federal Council identified the
limits of the adopted agricultural policy and
proposed a reorientation, which has been
successively implemented since 1993. The
core of the reform was to separate price and
income policies and to introduce product
independent direct payments as recom-
pense for agricultural performances which
are of common and ecological interests. To
achieve the environmental targets, the Fed-
eral Council fixed a hierarchy of priorities
in the Seventh Agriculture Report for the
following, currently effective, strategies:� Research, education and consulting:
farmers should be able to act in an environ-
mentally sound manner based on their own
knowledge and conviction.� Creation of financial and other incentives:
an environmentally sound management
must also be economically viable.� Additional regulations and guidelines in
different areas.
The focus of agricultural policy since 1993
has been point 2 of this strategy. On 9 June
1996, the public and the parliament in-
cluded a new agricultural article [2] in the
constitution. Since then, the confederation
is obliged to ensure that agriculture, via sus-
tainable and market-oriented production,
contributes substantially to secure an ade-
quate food supply for the population, the
maintenance of the natural life resources,
the care of the rural landscape, and a de-
centralized settlement of the countryside.
The confederation subsidized the farmers’
income through direct payments with the
aim of a fair and appropriate recompense for
the provided services. Prerequisite for this
is that agricultural enterprises provide a
Proof for Environmental Performance (PEP).
In addition, the confederation promotes
economic incentives for production forms
which are particularly natural, environmen-
tally and animal friendly. The ecological
dimension of sustainability becomes, thus,
an important objective of agricultural policy.
Direct Payments Since 1999Since 1999, the constitutional article has
become effective law [2]. The proof for envi-
ronmental performance covers:� husbandry of livestock in animal-friendly
conditions,� a regulated fertilizer balance,� a suitable proportion of ecological com-
pensation areas,� a regulated crop rotation,� suitable soil protection,� the choice and targeted use of plant treat-
ment products.
Of particular importance for water protec-
tion is the promotion of a regulated fertilizer
balance. It demands, on the one hand, that
farmers do not apply more nitrogen and
phosphorus than the cultivation and pasture
require. On the other hand, for environmen-
tal compensation, unfertilized grass verges
should be provided alongside waterbodies
of at least 3 m width (Fig. 1) and along paths
of at least 0.5 m width. Such green strips
reduce the input of fertilizers and auxiliary
agents into waterbodies.
Additional Water ProtectionMeasuresIn 1994, federal ministers Ruth Dreifuss and
Jean-Pascal Delamuraz commissioned a
workgroup with the task of defining targets
and measures for the reduction of nitrogen
emissions [3]. Using model calculations for
the future agricultural policy of Switzerland,
the workgroup came to the conclusion that
the then current measures – the reduction
of produce prices, direct payments and the
consistent execution of the Swiss Water
Pollution Control Law and the Swiss Ordi-
nance on Environmentally Hazardous Sub-
stances – were insufficient to achieve the
desired water quality in all locations.
More far-reaching measures could be nec-
essary, for example, in areas with ground-
water resources which are impacted by an
increased nitrogen runoff resulting from
7 EAWAG news 59
sen, Vaud and Zurich. Further nitrate and
phosphorus projects, and a project in the
westerly part of Switzerland dealing with
plant protection agents are in the planning
stage.
Positive Results in the FirstPilot ProjectsThe first pilot projects in accordance with
Article 62a of the Water Pollution Control
Law are currently being completed. After
6 obligatory project years, the results are
consistently positive. For example, the
nitrate project around the drinking water
catchment of Frohberg in Wohlenschwil
(Canton Aargau) was started as a pilot proj-
ect in 1996 and has been funded by the con-
agricultural activities. Through Article 62a
of the Water Pollution Control Law [4], in
1998 the Federal Parliament created an in-
strument for improving the quality of ground
and surface water bodies exposed to
agricultural emissions through targeted
financial incentives to farmers. Article 62a
of the Water Pollution Control Law provides
the confederation with the means of adding
federal subsidies to the contributions of
cantons or third parties in support of agri-
cultural policy measures. The requisite
funds would be provided through direct en-
vironmental payments in accordance with
the agricultural law. The emphasis is on re-
ducing nitrate loads in ground water and
phosphorus loads in surface waters. Includ-
ed are also measures designed to prevent
contamination of water bodies by plant pro-
tection agents.
Reducing the Nitrate andPhosphorus LoadsAccording to the Water Pollution Control
Ordinance, the cantons are obliged to de-
lineate inflow areas for above ground and
underground water catchments, and to im-
pose remedial action in case of insufficient
water qualities. Such measures can have
significant constraints with regard to land
use and, thus, lead to unsustainable finan-
cial consequences for the farms. If the
measures, however, are integrated into a
project, finance can be requested from the
confederation. It can be up to 80% of the
total costs for structural and management
adjustments, and up to 50% for technical
production measures. In 2003, around 4 mil-
lion Swiss francs were allocated.
Typically, problem solving is based on local
measures, which can be defined in co-
operation with the agricultural stakeholders.
Of particular suitability for environmental
measures are meadows and arable land
with green crop rotations. Since 1999,
18 nitrate and three phosphorus projects
have been submitted and approved. They
are located in the cantons of Aargau, Berne,
Freiburg, Lucerne, Solothurn, Schaffhau-
federation since 2001. It covers a catchment
area of total 102 hectares. 62 hectares of
these are agricultural land, encompassing
12 farms. The use of around 50 hectares is
controlled by a drinking water contract. It
contains strict, multi-year restrictions on the
application of nitrogen-containing mineral
and waste fertilizers as well as farm manure,
and cultivation restrictions for crops with
large runoff potential. In addition, there are
far-reaching constraints on soil processing
and crop rotation:� the extension of the utilization period for
temporary pastures,� conversion to extensively used and un-
fertilized meadows,� direct sowing of grassland,
Nitr
ate
conc
entr
atio
n (m
g/l)
1986 1988 1990 1992 1994 1996 1998 2000 2002 20040
10
20
30
40
50
60
Year
Fig. 2: Change in nitrate content in the Frohberg source in Wohlenschwil, Canton Aargau. The source is located in aproject area in accordance with Article 62a of the Water Pollution Control Law [3].
Fig. 1: A 3-m wide green strip reduces the input of fertilizer and plant protection agents into waterbodies. Worble inCanton Berne.
BLW
Conrad Widmer, Dip. Agro-Eng.ETH, head of the EcologicalDirect Payments Section in theFederal Office for Agriculture.He is concerned with the pro-motion of environment andanimal friendly production tech-niques in the agricultural sector.
Co-author: Simone Aeschbacher, Federal Office forAgriculture, Berne.
EAWAG news 59 8
� Remedial action will be undertaken where
problems exist.� The principle behind remediation is orient-
ed on the procedure laid down by Article
62a of the Water Pollution Control Law.
Thus, the cantons have both the responsi-
bility and the room for action. The confeder-
ation participates subsidiary.� Monitoring on the basis of the agroecolog-
ical indicators reveals whether the measures
are producing the desired results.
Watercourse Policy ModelSwitzerlandIn a broad co-operation, the Federal Offices
for the Environment, Forests and Land-
scape, for Water and Geology, for Agricul-
ture and for Spatial Development, have
designed guiding principles for Swiss wa-
tercourses [6, 7].
This document should provide guidelines
for a sustainable strategy for water policy on
all management levels. Three development
objectives stand in the foreground:� adequate space for watercourses, � adequate water flows,� adequate water quality.
In particular the development goal “ade-
quate space for watercourses” is a great
challenge for agriculture. Sustainable flood
protection and the demands which a water-
course must meet for its environmental
functionality, can only be achieved where a
sufficiently large area is allocated to the wa-
tercourse. This requires innovative solutions
to satisfy all the stakeholders involved.
A Glance over the BorderDespite intensive consultation and financial
support via state-sponsored environment
and support programmes, the agricultural
sector in the European Union (EU) remains
the main source of widespread pollutant
inputs to waterbodies. This is particularly
� rotary band seeding of maize,� direct sowing of winter cereals and� limitations in free range husbandry of pigs.
These measures have resulted in a reduc-
tion of nitrate concentrations to below the
target level of 25 mg/l (Fig. 2). If this success
in nitrate reduction is to be maintained with
certainty, the measures must be continued.
Agricultural Policy 2007On 1 January 2004, the Agricultural Law of
1999 was revised for the first time. The agro-
ecological aims relevant for water protec-
tion, which should be achieved by 2005, are
summarized in Table 1 [5].
One aim is the reduction of environmentally
relevant nitrogen losses from agriculture by
22 000 t to 74 000 t per year by 2005 start-
ing at the 1994 level of 96 000 t. This target
will most likely not be achieved. Although
the nitrogen emissions between 1990 and
1998 have fallen, they increased again in
2002. For nitrate, on the other hand, it
appears that the target will most likely be
achieved. Various investigations indicate a
trend in this direction. In addition, the meas-
ures according to Article 62a of the Water
Pollution Control Law are showing their
effectiveness within the nitrate projects. The
aim, to reduce the applied quantity of plant
protection agents to 1500 t per year, has
already been achieved. The environmentally
relevant phosphorus losses may not exceed
10 000 t per year. This target has also been
achieved, in fact already by the mid 1990s.
Regions with high concentrations of live-
stock remain problematic, and in these
areas phosphorus excesses still need to be
reduced.
The Federal Office for Agriculture therefore,
in conjunction with a workgroup, has devel-
oped a recommendation for the reduction
of the phosphorus excess. The solution is
based on the following principles:
the case for nitrate and plant protection
agents. At the end of June 2003, the EU
agricultural ministers passed a fundamental
reform of the Common Agriculture Policy,
which will change the support mechanisms
of the Union’s agricultural sector. The envi-
ronmentally relevant core points of the re-
form are:� Decoupling financial assistance from pro-
duction. In the coming years, most assis-
tance schemes will be provided independ-
ently of production volumes. The link to
production can be maintained to a limited
degree, to avoid production shutdown.� The new single operative payments will in
the future be linked to respecting environ-
ment, food safety and animal welfare stan-
dards (“Cross Compliance”). Agricultural
businesses will be subject to an annual
audit. Cross Compliance is fundamental
for the area-wide protection of waterbodies
and soil.� Reduction of direct payments to big enter-
prises (modulation). Thus, funds will be
freed for the development of regional areas
with new programmes in the fields of envi-
ronment, quality and animal protection.
Compared to the EU, Switzerland takes a
leading role in the protection of waterbodies
from agricultural inputs through the Proof for
Ecological Performance and the regional
programmes.
[1] Schweizerischer Bundesrat (1992): Siebter Bericht
über die Lage der schweizerischen Landwirtschaft und
die Agrarpolitik des Bundes, EDMZ 3003 Bern.
[2] Bundesverfassung der Schweizerischen Eidgenossen-
schaft (1999): Artikel 104 Landwirtschaft.
www.admin.ch/ch/d/sr/101
[3] BUWAL (1996): Strategie zur Reduktion von Stickstoff-
emissionen, BUWAL, Bern, 142 S.
[4] Bundesgesetz über den Schutz der Gewässer (1991):
§62a Massnahmen der Landwirtschaft.
www.admin.ch/ch/d/sr/c814_20.html
[5] Schweizerischer Bundesrat (2002): Botschaft zur
Weiterentwicklung der Agrarpolitik (Agrarpolitik 2007),
EDMZ, 3003 Bern.
[6] BUWAL, BWG, BLW, ARE (2003): Leitbild Fliess-
gewässer Schweiz, BBL, Bern.
[7] Willi H.P. (2002): Synergism Between Flood Protection
and Stream Ecology – Space as the Key Parameter.
EAWAG news 51, 26–28.
Agroecologicalarea
Measuredparameter
Basis Goals 2005
Agriculturalprocesses:ecological totalimpact tolerance
N balance
P balance
96 000 t N (1994)
About 20 000 t P(1990/92)
Maintain the nitrogen loss potentialto the level of 74 000 t N per year.This corresponds to a reduction ofabout 22 000 t N (circa 23%) com-pared to the 1994 level.
Reduction of P excess by 50% toaround 10 000 t P. This level wasmaintained.
Agricultural practice(consumption)
Plant protectionagents
About 2200 t activeagents (1990/92)
Reduction of the total applied plantprotection agents by 30% toaround 1500 t active agents.
Effects on theenvironment
Nitrate In 90% of the drinking water catch-ments, where inflow areas are usedby agriculture, the nitrate levels arebelow 40 mg/l.
Tab. 1: Goals of the Swiss Agricultural Policy till 2005, N = nitrogen, P = phosphorus.
9 EAWAG news 59
Contaminated Drinking Water from Agricultural Areas?
Drinking water from rural catchments is normally either not at allor minimally treated. It is precisely this water which can be con-taminated by liquid manure or excrement from grazing animals.The most worrying aspect are the environmentally persistent formsof cryptosporidia. In 9 out of 15 investigated drinking water catch-ments in rural areas, we could in fact detect cryptosporidia. It isstill to be determined whether they present a hazard for humans.
also contaminated with faecal bacteria
E. coli (Fig. 2). The water from these catch-
ments, therefore, did not meet the quality
criteria for drinking water. For the remaining
5 catchments contaminated with cryp-
in karst spring water [2] and 0.25 oocyst/l
in drinking water [3]. Our measurements are
comparable to these findings.
In addition, 4 out of 9 Cryptosporidium
containing drinking water catchments were
The officially prescribed microbiological
drinking water tests are limited to the detec-
tion of E. coli and enterococci, and the total
plate count. Persistent pathogenic bacte-
ria such as cryptosporidia (see box p. 10)
therefore remain undetected. While E. coli
die relatively quickly in the environment,
the persistent form of Cryptosporidium, the
so-called oocyst (Fig. 1), remain infectious
for weeks to months. Cryptosporidia also
survive in chlorinated drinking water, as
opposed to E. coli. Therefore, water which
otherwise fulfills the quality criteria for drink-
ing water can still contain disease causing
pathogens.
Particularly affected are drinking water
catchments in agricultural areas, since this
water can come into contact with grazing
animal excrement and liquid manure. Ani-
mals which are infected with cryptosporidia
excrete infectious oocysts which can reach
drinking water. Since this water is usually
not treated in any way, EAWAG wanted to
estimate how great the risk was for a Cryp-
tosporidium infection through the consump-
tion of drinking water in agricultural areas.
Cryptosporidia are RelativelyWidespreadWe took water from 15 small rural area
drinking water catchments in different parts
of Switzerland. The drinking water was ex-
amined not only using the analysis pre-
scribed in the food and drink regulations,
but also for cryptosporidia (see box p. 10).
9 out of 15 of the water samples were con-
taminated with cryptosporidia (Fig. 2). To
date, Cryptosporidium concentrations have
been detected in Switzerland of up to 3.83
oocyst/l in surface waters [1], 1.6 oocyst/l
Fig. 1: Under a standard optical microscope, a Cryptosporidium oocyst is hardly visible (A). Specific fluorescentantibodies cause the oocyst surfaces to light up (B). In the small intestine of the host, the Cryptosporidium oocystsgerminate (C) and release 4 sporocytes – a process known as excystation. The sporocytes enter the intestinalepithelium and create new oocysts there.
0.45
Cry
pto
spor
idiu
m (o
ocys
ts/l)
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
Ber
ne 1
Uri
1
Ber
ne 2
Gla
rus
Vau
d 1
St.
Gal
len
1
Ob
wal
den
1
Vau
d 2
Uri
2
Gris
ons
1
Ob
wal
den
2
Vau
d 3
St.
Gal
len
2
Tici
no
Val
ais
E.c
oli (
num
ber
/100
ml)
6
5
4
3
2
1
0
9
8
7
Gris
ons
2
cryptosporidiosis can occur
cryptosporidiosis is almost unavoidable
Cryptosporidium
E. coli
Fig. 2: Measured Cryptosporidium and E. coli concentrations in 15 drinking water catchments of rural areas dis-played in descending order of oocyst concentrations. Berne 1 is a public fountain. In the range of 0.1–0.3 oocysts/ldisease outbreaks in the population can be expected, above 0.3 oocysts/l epidemics are possible.
A B C
Pho
togr
aphs
: EA
WA
G
EAWAG news 59 10
tosporidia, the E. coli indicator had not de-
tected the faecal contamination. In another
catchment we detected E. coli but no cryp-
tosporidia.
Clostridium is not an Indicatorfor CryptosporidiaThe Drinking Water Guideline from the Euro-
pean Union [4] declares the bacterium
Clostridium perfringens, which can survive
for extended periods in the soil with help of
its spores, as persistent faecal indicator on
the basis of the following assumption: if in
100 ml drinking water there are no clostridia
detectable, the water should also be free of
any other persistent parasite forms such as
Cryptosporidium oocysts.
If this association is correct, then water
samples which are contaminated with Cryp-
tosporidium should also contain Clostridi-
um. We wanted to test this hypothesis and
analyzed water samples of the 15 drinking
water catchments also for Clostridium.
However, we found no correlation between
the occurrence of Cryptosporidium and the
persistent faecal indicator C. perfringens.
Only two drinking water catchments were
contaminated with clostridia: in Glarus cryp-
tosporidia as well as clostridia were present
(1 spore in 100 ml water), while the investi-
gated drinking water catchment in Ticino
contained no cryptosporidia but 96 Clostrid-
ium sporidia in 100 ml water. It is therefore
doubtful that C. perfringens can be used as
an indicator for Cryptosporidium. Most like-
ly, clostridia and cryptosporidia are not sim-
ilar enough in their environmental behavior.
The Situation in SwitzerlandLegal regulations for defining threshold lim-
its for cryptosporidia in drinking water exist
neither in Switzerland nor abroad. There is
therefore uncertainty as to how to assess
the hazard presented by the presence of
cryptosporidia in drinking water.
Even a Cryptosporidium concentration of
0.1 oocyst/l can lead to disease outbreaks
in the population, and concentrations of
more than 0.3 oocyst/l will almost certainly
lead to cryptosporidiosis cases [5]. In 20%
of the drinking water samples we investi-
gated, the Cryptosporidium concentration
was above 0.1 oocyst/l and exceeded in one
case even the value of 0.3 oocyst/l (Fig. 2).
In 9 of the 15 drinking water catchments
the risk level assessed in the USA as a 10– 4
residual risk for cryptosporidiosis was ex-
ceeded (1 infected person per 10,000 per-
sons per year, at an oocyst concentration of
more than 0.0000327 oocyst/l). Since our
measurements are just momentary sample
extractions, it must be assumed that after
large precipitation events, the Cryptosporid-
ium concentration will rise considerably.
So Far No CryptosporidiumEpidemics in SwitzerlandDespite this noteworthy count of cryp-
tosporidia in the tested drinking water,
Switzerland has so far been spared an epi-
demic. The prevalence of diarrhea cases –
i.e. the percentage of the Cryptosporidium
contaminated diarrhea patients at a given
time – is in Germany and Switzerland for the
general population at 0.4–1.9%. Children
are harder hit, at a rate of 1.1–4.8%, while
Cryptosporidia
What are cryptosporidia?Cryptosporidia are protozoal intestinal parasites of considerable diameter (5 µm diameter),which create oocysts in a persistent form (Fig. 1). They belong to the most important pathogenicprotozoa in drinking water. The Cryptosporidium genus contains 13 species. Cryptosporidiumparvum is the most widespread and pathogenic also for humans. C. parvum is thought to beable to infect any mammal [6].
What are the symptoms of a Cryptosporidium infection?The disease contracted through cryptosporidia, cryptosporidiosis, is a zoonosis – i.e. an animaldisease which can be transferred to humans. Human infections were first documented in 1976and water-borne cryptosporidiosis has been known since 1984. Since then a number of epi-demics occurred in the USA, Great Britain and Japan: the largest estimate of cases being400 000 in 1993 in Milwaukee (Wisconsin, USA) [7]. The oocysts excreted with faeces stay alivein cold water for several months. Cryptosporidiosis begins with the intake of oocysts (Fig. 1A+ B). After an incubation period of 2 to 12 days, in which the oocysts germinate in the intestine(Fig. 1C) and multiply, the infection leads to watery diarrhea and stomach cramps, usually with-out temperature rise, nausea, faintness, or vomiting. The sickness onset is variable, but nor-mally the disease cycle is over within 30 days. However, for people with weakened immune sys-tems, especially HIV positive cases, the infection takes a chronic or fulminant course, and caneven lead to death in some exceptional cases. To date, there is no medication available fortreating cryptosporidia.
How are Cryptosporidia detected?The American environmental authorities and the British Drinking Water Inspectorate recom-mend Detection Method 1623 for Cryptosporidium in drinking water. In the field a large volumeof water, 100 to 1000 l, is passed through a filter with 1 µm pores. In the laboratory, the particlesare dissolved from the filters and the cryptosporidia separated from the other particles with help of immunomagnetic methods. The cryptosporidia are colored by surface antibodies andcounted under a fluorescent microscope (Fig. 1B).Active oocysts from environmental samples can be brought to germination in suitable mediaand temperatures of 37 °C in laboratory cultures. In this way, the percentual proportion of activeoocysts in drinking water can be determined.
Fig 3: Manure spreading and ...
Pho
togr
phs
: EA
WA
G
Hans Peter Füchslin, environ-mental scientist, is a post-doctoral fellow in the DrinkingWater Microbiology Group with-in the Department of Environ-mental Microbiology. Researchinterest: drinking water micro-biology, pathogen detection.
Co-author: Thomas Egli
11 EAWAG news 59
the value rises for AIDS patients to 11.8%. It
is calculated that in Switzerland annually
there are 340 cryptosporidiosis cases [8]. In
reality, only a few are clinically identified.
This could be due to the following reasons:� Cryptosporidia originating from cattle are
less infectious than first thought. With the
detection methods we use, Cryptosporid-
ium species which are either not at all or
little pathogenic are also detected.� Cryptosporidia in drinking water are no
longer necessarily vital or infectious. De-
pending on the environmental conditions,
oocysts can survive for several months.
They die in time, but remain detectable.� People who are sick with cryptosporidio-
sis seldom consult a doctor. Consequently,
clinical tests are not usually made for cryp-
tosporidia.� The public consumes very little unboiled
water.
Practical ConsequencesThe regulations in the current legislation for
drinking water in specified groundwater pro-
tection zones must be better respected.
Close to drinking water catchments, in the
so-called groundwater protection zone I, all
grazing and fertilizer usage is forbidden [9].
These regulations are not always complied
with, as Fig. 3 shows. Periodic inspections
are therefore necessary. Above all, bad
weather can raise the risk of faecal matter
being washed into drinking water catch-
ments. Therefore, for certain locations with
poor soil filtration, it may be necessary to
[1] Regli W. (1994): Verbesserte Methoden für die Isolie-
rung und den Nachweis von Giardia-Zysten und
Cryptosporidien-Oozysten in Oberflächengewässern:
Flockung mit Al2(SO4)3 und fluorescence-activated
cell sorting (FACS). Veterinärmedizinische Fakultät,
Universität Zürich 70 S.
[2] Auckenthaler A., Raso G., Huggenberger P. (2002):
Particle transport in a karst aquifer: natural and artifi-
cial tracer experiments with bacteria, bacteriophages
and microspheres. Water Science & Technology 46,
131–138.
[3] Svoboda P., Ruchti S., Bissegger C., Tanner M. (1999):
Occurrence of Cryptosporidium spp. oocysts in sur-
face, raw and drinking water samples. Mitteilungen auf
dem Gebiete der Lebensmittelhygiene, 553–563.
[4] Council Directive 98/83/EC on the quality of water
intended for human consumption:
http://europa.eu.int/scadplus/leg/en/lvb/l28079.htm
[5] Haas C.N., Rose J.B. (1995): Developing an action
level for Cryptosporidium. Journal Journal American
Water Works Association 87, 81–83.
[6] Xiao L., Fayer R., Ryan U., Upton S.J. (2004): Crypto-
sporidium taxonomy: recent advances and implica-
tions for public health. Clinical Microbiology Reviews
17, 72–97.
[7] Smith H.V., Rose J.B. (1998): Waterborne Crypto-
sporidiosis: Current status. Parasitology Today 14,
14–22.
[8] Baumgartner A., Marder H.P., Munzinger J., Siegrist
H.H. (2000): Frequency of Cryptosporidium spp. as
cause of human gastrointestinal disease in Switzer-
land and possible sources of infection. Swiss Medical
Weekly 130, 1252–1258.
[9] Gewässerschutzverordnung (1998):
www.admin.ch/d/sr/c814_201.html
treat the water by means of, for example, UV
disinfection.
Implications for FurtherResearchThere is a general uncertainty whether peri-
odically higher Cryptosporidium concentra-
tions, which are to be expected after heavy
precipitation, represent a hazard for con-
sumers of drinking water. Too little is known
about the exact species allocation of cryp-
tosporidia which occur in Switzerland, and
the vitality of oocysts in drinking water, to
provide a clear answer to this question.
In a further stage of the project, we would
like to close some of these gaps in our
knowledge. For this purpose, at three loca-
tions with high oocyst concentrations, the
vitality should be determined by sporulation
tests (see box p. 10), and the exact species
of Cryptosporidium should be characterized
through genotyping. In addition, a risk as-
sessment should be made on the basis of
results obtained. We would also like to sur-
vey the local authorities and physicians con-
cerning whether in the past years there has
been any increase in the number of cryp-
tosporidiosis cases in the population.
Cryptosporidia, even if they are classed as
weak pathogens in further investigations,
are environment persistent faecal indica-
tors, which should be excluded in any case
from drinking water.
We would like to thank “Labor Spiez” for the
funding of the project.
... pasture grazing can lead to animal faecal contamination of drinking water catchments.
EAWAG news 59 12
Use of Antibiotics in Agriculture –Consequences for the Environment
After their use in animal husbandry, sulphonamide antibiotics arespread with the liquid manure onto the farmland. Despite aninitially rapid decrease of the concentration in the soil, residualamounts remain detectable for months. In addition, rain can washthe antibiotics out of the soil into neighboring water bodies. Afurther problem is the presence of antibiotic resistant bacteria inthe liquid manure. To what extent the use of antibiotics promotesthe development and distribution of resistant bacteria is still un-clear.
Antibiotics were hailed in the first half of the
twentieth century as a miracle cure against
bacterial infections. First used in human
medication, they are today also indispen-
sable in animal husbandry (see box “Use
of antibiotics in animal husbandry”), and
around 40 tonnes are applied in Swiss agri-
culture annually. However, their use involves
two basic risks:
The first is that antibiotics, in part still active,
in part in a derivative product form, enter the
environment through animal excrements
which are applied onto the agricultural land
as liquid and solid manure. Thus, as much
as a few hundred grams of antibiotics per
hectare and year might be dispersed. Rain
washes the antibiotics into the neighboring
water bodies, but the precise fate of the
antibiotics in the environment is still little
understood. The second risk is that the anti-
biotics promote the development of resist-
ant bacteria in the animals under treatment.
Through the process of natural selection,
mutations can create new resistance genes,
and these, together with those already pres-
ent in the bacterial community, can be
passed on to other bacterial strains and
species, resulting in a rapid dispersal of
the resistance genes. If the resistance gene
gets transferred to pathogenic bacteria, the
results can be fatal, as these bacteria can no
longer be combated by available antibiotics.
The World Health Organization WHO ranks
the problem of development and transfer of
resistance genes as particularly serious, and
sees the need for urgent action. To date, it is
still unclear how great the risk of resistance
development and dispersal is for the agri-
cultural environment.
In a joint research project, we are, therefore,
studying both the behavior of antibiotics in
the environment and – by means of select-
ed resistance genes as probes – the pres-
ence of resistant bacteria in agricultural soil.
We are specifically interested in knowing
whether a relationship exists between the
use of antibiotics in agriculture and the
appearance of resistance genes in the envi-
ronment. Our project is part of the Swiss
National Fund Research Program 49 “An-
tibiotics Resistance” [1].
Field Study Under SwissAgricultural PracticeStarting point of our investigation was the
consideration to carry out a field trial under
practical conditions. Therefore, we spread
liquid manure polluted with antibiotics on
two perennial grassland lots of each 0.35 ha.
The applications were made at the start of
the vegetation period, on 24 March 2003,
and after the first cut on 8 May 2003. The
manure was applied using the band spread-
er technique (Photo 1). It was delivered from
a pig feeder farm where the sulphonamide
antibiotic sulphamethazine had been used
as stabling prophylaxis (see box “Special
case: sulphonamide antibiotics”). The sul-
phamethazine concentration in the fresh
manure was 15 mg/kg – a heavy but realis-
tic load [2].
Over a time period of four months prior and
subsequent to application of the manure,
soil samples were taken from the plots
(Photo 2). Using a meteorological station
directly on the lots, different parameters
were recorded continuously, the most im-
portant of which was rainfall (Photo 3). Since
both pastures were situated alongside a
small stream, it was possible to determine
the input of antibiotics into the stream wa-
Use of Antibiotics in Animal HusbandryAntibiotics used in animal husbandry originate essentially from the same substance groups ashuman antibiotics: penicillins, tetracyclines, sulphonamides, macrolides, aminoglycosides, andfluorochinolone.In veterinary medicine, antibiotics are used in the treatment of individual sick animals and inpreventive treatment for the entire stock of animals. The procedure of preventive dosing theentire herd with antibiotics once a disease makes an appearance, for example when piglets orcalves suffer from diarrhea or respiratory disease, is known as metaphylaxis. Prophylaxis, onthe other hand, is applied before any of the animals fall ill, and is used, for example, to preventinfection during stabling of fattening animals from different farms.
Special Case: Sulphonamide AntibioticsThere were a number of reasons for usingliquid manure containing the sulphonamideantibiotic sulphamethazine in our fieldstudy:� Sulphonamides are common in veterinarymedication (e.g. in stabling prophylaxis).Mainly one active substance (sulpha-methoxazole) from this group is used inhuman medicine.� Sulphonamides are only moderatelymetabolized in animal organisms and rela-tively quickly excreted [2]. It is exceptionalthat the metabolites in the manure revertalmost entirely to the original active agentform [3]. For our investigation, it is partic-ularly important that the sulphonamidesendure in the environment and are, there-fore, detectable over a long time period.� At EAWAG methods have been devel-oped for the determinatiom of sulpha-methazine in liquid manure [4], in soil [5]and in water [unpublished].
13 EAWAG news 59
Resistance gene Origin
sul (I) Escherichia coli (non-pathogenic)
sul (II) E. coli
sul (III) E. coli
tet (B) E. coli
tet (C) E. coli
tet (H) Pasteurella multocida (opportunistic pathogen)
tet (M) Enterococcus faecalis (opportunistic pathogen)
tet (O) Campylobacter coli (pathogenic)
tet (Q) Bacteroides thetaiotaomicron ( non-pathogenic, found in human gastro-intestinal tracts)
tet (S) Listeria monocytogenes (opportunistic pathogen)
tet (T) Streptococcus pyogenes (opportunistic pathogen)
tet (W) Butyrivibrio monocytogenes (anaerobic rumen bacterium)
tet (Y) aus Schweinegülle isoliertes Plasmid (unknown bacterium)
tet (Z) Corynebacterium glutamicum (soil bacterium)Pho
togr
aphs
EA
WA
G
IRA
S, U
nive
rsity
of
Utr
echt
Tab. 1: Investigated resistance genes and their origin. The bacteria from which the different resistance genes werefirst isolated and sequenced are shown. All resistance genes could subsequently be detected in other bacterialstrains; tet (B), for example, was found up to now in 18 different strains. In most cases the presence of one of the various tetracycline or sulphonamide resistance genes was sufficient to make the carrier bacterium resistant to tetracyclines or sulphonamides, respectively. Opportunistic pathogens do not always cause disease, only forimmunologically weakened patients.
ter. For this purpose, we built a measuring
station 500 m downstream, which continu-
ously measured the waterflow and automat-
ically took water samples (Photo 4).
At EAWAG, we determinated the sulpha-
methazine concentrations in the soil (Pho-
to 5) as well as in groundwater and stream
water samples. In addition, the manure and
soil samples were analyzed at the University
of Utrecht by means of molecular biological
methods for the presence of 14 different
antibiotic resistant genes (Photo 6). 11 of
the investigated genes are tetracycline re-
sistance genes, the remainder are oriented
against sulphonamides (see Tab. 1). With
the applied technique, changes in the pres-
ence of the studied resistance genes are
detectable providing qualitative or at best
semi-quanitative information.
Higher Antibiotic Load in SoilAfter ManuringFigure 1 shows the sulphamethazine con-
tent of the soil before and after the two
manure applications. The sulphamethazine
concentrations are expressed as average
values over the entire lot, whereas local val-
ues can be as much as five times higher due
to the heterogeneity. Before the first manur-
ing, no sulphamethazine could be detected
in the soil. After the manuring, the concen-
tration leapt up and then fell over time. One
day after the manuring, only 10% of the
extracted amount was found in the soil pore
water. The rest of the sulphamethazine
was sorbed to soil particles or had been
transformed. Only a few days later, sulpha-
methazine concentration in the soil had
1
2
3
4
5
6
EAWAG news 59 14
decreased further. During the next weeks,
concentration remained relatively stable, so
that the values at the time of the second
manuring had not returned to zero. After the
second application, the sulphamethazine
concentration increased again.
13 of the 14 Resistance GenesDetectableIn the liquid manure used, we could detect
13 of the 14 tested resistance genes. We
found at most 12 of the 14 genes (Fig. 1)
in the soil samples. As opposed to sulpha-
methazine, various resistance genes were
already present in the soil before the first
manure application. 8 and 11 genes were
clearly detectable in the two lots. Additional
1–4 genes gave only weak signals, indicat-
ing a probable low amount in the soil.
After manuring, the intensity of the resist-
ance gene signals increased and 10–12
of the 14 resistance genes were clearly
detectable over weeks (Fig. 1). We assume
that these additional genes derive from the
microflora of the manure.
Weather Determines the Fateof the AntibioticsInterestingly, the weather after the two ma-
nure applications was very different. Where-
as the first manuring was followed by a dry
week without any rain and a precipitation
poor April (60% of the long-term average),
the week after the second application was
very wet. This had a decisive effect on the
fate of the sulphamethazine in the environ-
ment.
We found that the total sulphamethazine
content of the soil increased less strongly
after the second manure application with
subsequent rain than after the first applica-
tion without rain (Fig. 1). This was also the
case for the sulphamethazine concentra-
tions in the pore water: after the first manur-
ing without rain, they were nearly twice as
high (approx. 65 µg/l) as after the second
manuring with rain (approx. 35 µg/l). In ad-
dition, a higher sulphamethazine concentra-
tion could be detected in the stream water
after the second manure application. It
reached a maximum of 4 µg sulphameth-
azine per liter water (Fig. 2) and was slightly
raised during the subsequent rainy period,
while the concentration peaks became
Sul
pha
met
hazi
ne c
once
ntra
tion
(µg/
kg)
Num
ber
of r
esis
tanc
e ge
nes
800 16
700 14
600 12
500 10
400 8
300 6
200 4
100 2
0 0–14 –7 0 7 14 21 28 35 42 0 7 14 21 28 35 42
Days after application
Sul
pha
met
hazi
ne c
once
ntra
tion
(µg/
kg)
Num
ber
of r
esis
tanc
e ge
nes
800 16
700 14
600 12
500 10
400 8
300 6
200 4
100 2
0 0–14 –7 0 7 14 21 28 35 42 0 7 14 21 28 35 42
1st manuring 2nd manuring
1st lot
2nd lot
Fig. 1: Concentrations of sulphamethazine (black curve, average values plus standard deviation) and number ofresistance genes (dark shaded area = clearly detectable resistance genes, light shaded area = additional, weaklydetectable resistance genes) in soil samples of the two perennial pasture lots. On 24 March 2003 and 8 May 2003,sulphamethazine-containing liquid manure (15 mg/kg) was spread onto the fields.
Perennial pasture was used as the test field.
EA
WA
G
gradually less pronounced, the more time
passed after the application. In contrast,
the sulphamethazine concentration in the
stream water after the first manuring at the
end of March was considerably lower.
Krispin Stoob, EnvironmentalScientist, currently working on his thesis in the group Waterand Agriculture in the Depart-ment of Environmental Chem-istry.
Co-authors Heike Schmitt, Institute for Risk Assessment Sciencesat the University of Utrecht and National Institute ofPublic Health and the Environment, Bilthoven, Nether-lands.Marcel Wanner, Professor at the Institute of AnimalNutrition at Zurich University.
15 EAWAG news 59
[1] www.nrp49.ch
[2] Vree T.B., Hekster Y.A. (1987): Clinical pharmaco-
kinetics of sulfonamides and their metabolites –
an encyclopedia. Antibiotics and Chemotherapy 37,
1–214.
[3] Langhammer J.P. (1989): Untersuchungen zum Ver-
bleib antimikrobiell wirksamer Arzneistoffe als Rück-
stände in Gülle und im landwirtschaftlichen Umfeld.
Dissertation, Universität Bonn, 138 S.
[4] Haller M.Y., Müller S.R., McArdell C.S., Alder A.C.,
Suter M.J.F. (2002): Quantification of veterinary
antibiotics (sulfonamides and trimethoprim) in animal
manure by liquid chromatography-mass spectrome-
try. Journal of Chromatography A 952, 111–120.
[5] Stettler S. (2004): Extrahierbarkeit und Transportver-
fügbarkeit von Sulfonamiden in Grünlandböden nach
Gülle-Applikation. Diplomarbeit, ETH-Zürich, 61 S.
[6] International Cooperation on Harmonisation of Tech-
nical Requirements for Registration of Veterinary
Products (VICH).
http://vich.eudra.org/pdf/2000/Gl06_st7.pdf
[7] Boleas S., Fernández C., Carbonell G.,Babín M.M.,
Alonso C., Pro J., Tarazona J.V. (2003): Effects
assessment of the antimicrobial sulfachloropyri-
dazine. Poster an der Envirpharma, Lyon:
www.envirpharma.org
[8] Thiele S., Beck I.-C. (2001): Wirkungen pharmazeuti-
scher Antibiotika auf die Bodenmikroflora – Bestim-
mung mittels ausgewählter bodenbiologischer
Testverfahren. Mitteilungen der deutschen Boden-
kundlichen Gesellschaft 96, 383–384.
[9] Schmitt H., van Beelen P., Tolls J., van Leeuwen C.L.
(2004): Pollution-induced community tolerance of
soil microbial communities caused by the antibiotic
sulfachloropyridazine. Environmental Science &
Technology 38, 1148–1153.
[10] Séveno N.A. Kallifidas D., Smalla K., van Elsas J.D.,
Collard J.M., Karagouni A.D., Wellington E.M.H.
(2002): Occurrence and reservoirs of antibiotic
resistance genes in the environment. Reviews in
Medical Microbiology 13, 15–27.
[11] Stanton T.B., Humphrey S.B. (2003): Isolation of
tetracycline-resistant Megasphaera elsdenii strains
with novel mosaic gene combinations of tet (O) and
tet (W) from swine. Applied and Environmental Micro-
biology 69, 3874–3882.
Further Investigation RequiredOur field study shows that the sulphon-
amide antibiotics can still be found in the
soil months after the manure applications.
The concentrations found in the soil clearly
exceeded the so-called trigger value of
100 µg per kg of soil. The trigger value is
defined as the threshold limit for the ap-
proval of new veterinary medications. If
exceeded, environmental impacts must be
evaluated in detail [6]. Results from other
studies indicate that sulphonamides can
have an effect on soil organisms: at a sul-
phonamide concentration of 1 mg/kg the
enzyme activity of soil bacteria changed [7]
leading to a reduction of soil respiration [8].
In our field study, these concentrations were
locally clearly exceeded due to the hetero-
geneity in the soil. In addition, we could
demonstrate that soil bacteria react with
increased tolerance to sulphonamide anti-
biotics above concentrations of 10 mg/kg
[9]. Therefore, it is crucial to investigate the
effects of such environmental concentra-
tions closer and to find out more about the
bioavailability of sulphonamide in soil.
Our measurements allowed us to confirm
the presence of resistance genes in both the
manure and the soil. The presence of re-
sistance genes in the environment is also
proved by other studies [10, 11]. However,
it still remains unclear whether additional
antibiotic resistance genes are introduced
with the manure into the soil. To be able to
answer this question definitively, we need to
quantify the genes. In addition, it is impor-
tant to investigate whether the resistance
genes are washed out of the soil by rain into
the water bodies, leading to further disper-
sal of the resistance genes. And finally, it
must be clarified whether an increased
presence of resistance genes in the environ-
ment influences the appearance of resist-
ance in pathogens.
Thus, it is currently not possible to carry out
a proper evaluation of the risks that exist in
the use of antibiotics in animal husbandry.
Too much detailed information is missing.
Nevertheless, our investigations lead us to
the conclusion that antibiotics should be
used carefully and with more awareness of
the inherent risks.
Sul
pha
met
hazi
ne c
once
ntra
tion
(µg/
l)
Wat
er r
unof
f (l/s
)
150
100
50
0
4
3
2
1
08.5.03 9.5.03 10.5.03 11.5.03 12.5.03 13.5.03 14.5.03
SulfamethazineWater runoff
2nd manuring
Fig. 2: Water runoff and sulphamethazine concentration in the stream during a rainy period after the secondmanure application on 8 May 2003.
EAWAG news 59 16
Pesticides in Water – Research Meets Politics
Pesticides have been consistently detected in high concentrationsin Swiss surface waters over a number of decades. The directpayments scheme introduced in 1993 for ecological measures inagriculture was designed to improve the situation. The goal wasto halve the pesticide pollution by the year 2005. A pesticidepollution analysis carried out by EAWAG in the Greifensee regionreveals that the target has not been fully achieved. Although therehas been a reduction in the total quantity of pesticides used, themeasures designed to reduce the pesticide loss from the treatedfarmland have largely failed to take effect.
With its innovative changeover from a prod-
uct-subsidized agricultural policy to one
that is environmentally and market-oriented,
Switzerland acts as a pacesetter in broad-
er Europe. Intangibles corresponding to
environmental services claimed by society,
which could not be traded on a free market
system, could only be funded by a subsidy
system involving direct payments by the
state to farmers (also see article by C. Wid-
mer, p. 6). This direct payments scheme
consumes 5% of the total federal budget,
i.e. around 2.4 billion Swiss francs per year.
Agricultural enterprises receive these funds
on the condition that they provide a proof
for ecological performance (PEP). Along
with measures such as regulated fertilizer
balance and crop rotation, the PEP also in-
cludes requirements for targeted selection
and application of pesticides. About 0.4 of
the 2.4 billion Swiss francs are allocated for
special environmental services, beyond
those specified in the PEP. These cover
subsidies for water protection and environ-
mental quality as well as contributions for
ecological compensation areas used for ex-
tensive grain and rape production (Extenso
Production), for organic agriculture and for
animal-friendly husbandry. With the intro-
duction of the direct payments scheme, the
number of farms participant in the PEP has
increased rapidly. Whereas in 1993 only
about 17% of agricultural land was man-
aged in compliance with ecological guide-
lines, today this proportion has increased
to 97%. Considering the enormous costs
involved in converting Swiss agriculture to
more ecological practices, it begs the ques-
tion as to how effective the measures are in
reality.
Goal: Halving the PesticidePollution of Water BodiesWith the start of the ecological compensa-
tion policy in 1993, concrete targets were
defined for ecological relevant parameters
such as biodiversity, nitrogen, phosphorous,
and pesticide loads, which should have
been achieved by the end of 2005. The tar-
get for pesticides was to reduce the pollu-
tion by half. Two actions should be taken:
a 30% reduction in the total quantity of pes-
ticide applied and the remaining 20% being
achieved through loss limitation measures
(see box: Measures).
This article attempts to answer the question
of whether the pesticide load since the intro-
duction of the ecological measures in 1993
has in fact been reduced. One logical start-
ing point in judging the success of the
measures is the analysis of pesticide sales
figures. More direct information, though, is
available from long-term pesticide pollution
analyses of water bodies, for which pesti-
cide concentrations are measured. With
interruptions, EAWAG has carried out such
investigations since 1991 in the Greifensee
(see Box: Pollution Analyses). Since 1997,
they have been financed by the Federal
Department of Agriculture as part of the
project “Evaluation of ecological measures”.
Declining Pesticide SalesFigure 1 shows that pesticide sales by vol-
ume [1] decreased between 1993 and 2003
by about 25%. It is not possible, however,
Measures Involved in the Proof of Ecological PerformanceMinimization of pesticides used:� Application of the threshold principle: pesticides are only used if the expected damage by
pests exceeds the cost of application.� Take advantage of natural regulation mechanisms: indirect plant protection, e.g. adapted
variety selection and crop rotation.� Encourage the insecticide and fungicide-free extensive production (Extenso Production) of
grain and rape.� Encourage the pesticide-free organic agriculture.
Minimization of pesticide losses:� 3-meter wide buffer strips alongside streams and lakes (see article by C. Widmer, p. 6).� Erosion prevention measures (e.g. winter plant cover).
Filling the tank of a sprayer with a pesticide mixture.
Pho
togr
aphs
: EA
WA
G
17 EAWAG news 59
Act
ive
ingr
edie
nts
(t)
2500
2000
1500
1000
500
01988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
Plant growth regulators
Insecticides
Herbicides
Fungicides
Fig. 1: Pesticide sales data for the period 1988 to 2003 [1].
to conclude from this figure that there has
also been a 25% reduction in pesticide use.
One reason for this is that pesticides import-
ed from abroad, and pesticides stored on
farms, are not included in this figure. An-
other reason is that the amount of land
under cultivation has reduced significantly
over the past 10 years. Adjusting the figures
accordingly lowers the effective pesticide
reduction to only 20%, i.e., from 6.5 kg per
hectare to 5.4 kg. Furthermore, the market
has been supplying an increasing number of
new pesticides which require much lower
quantities in application to gain the same
effects. The increased potency of the new
pesticides has consequences not only for
agricultural use, but also for the aquatic
ecosystems. A more meaningful indicator
for pesticide use should be based on an
adequate consumption survey and take into
account both the treatment intensity and the
potency of the pesticide.
Prominent Cereal and Maize HerbicidesThe collective term pesticide in Switzerland
covers around 400 approved individual sub-
stances. Sufficiently accurate and sensitive
analytical methods are available only for a
portion of the pesticides. A comprehensive
determination of pesticide pollution is there-
fore not possible.
For the pollution analysis at Greifensee,
around 50 of the 100 pesticides used in this
area were investigated. Herbicides from the
widespread maize and cereal cultivation are
regularly detected. One of these, the maize
herbicide atrazine, has been banned in oth-
er countries, such as Germany, but remains
one of the most used pesticides in Switzer-
land. Since the only data available for the
first half of the 1990s is for atrazine, having
been collected as part of other EAWAG
research projects before the start of the
national evaluation programme, this herbi-
cide was selected for a detailed analysis.
Decreasing Atrazine PollutionThe data available since 1990 for the
Greifensee region show that the quantities
of atrazine used during the 1990s fell from
Pollution Analysis of theGreifensee Lakes make ideal observation systems fora pollution analysis. With water residencetimes of usually several hundred days, allof the activities in the catchment area areintegrated, and, to the contrary of highlydynamic running waters, the loads (pesti-cide quantities entering the lake) can bemeasured at relatively low cost and overextended time periods [2]. On behalf of theSwiss Federal Office for Agriculture,EAWAG has been conducting a pollutionanalysis of the Greifensee since 1997. The160 km2 catchment area of the Greifenseeprovides a good overall picture of the vari-ous agricultural practices and the relatedpesticide sources and transport pathways.In addition, EAWAG already collected pes-ticide data from the Greifensee in the peri-ods 1990–1991 and 1993–1994. The mostcomprehensive data record exists for themaize herbicide atrazine.
Application of pesticides onto farmland.
EAWAG news 59 18
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003Year
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Tota
l am
ount
of a
traz
ine
in t
he la
ke (k
g)
50
45
40
35
30
25
20
15
10
5
0
B
A
Atr
azin
e q
uant
ity a
pp
lied
(kg)
0
200
400
600
800
1000
1200
Atr
azin
e lo
ad (k
g)
60
50
40
30
20
10
0
Atrazine quantity appliedAtrazine load
Fig. 2: More than a decade of Greifensee pollution by atrazine – (A) applied quantities in the catchment area and the quantities entering the lake (load), and (B) total quantity in the lake. Through combination of the monthly depth-profile measurements of pesticide concentrations with a lake simulation software, the atrazine load couldbe determined to sufficient precision [2].
over 1100 kg to about 400 kg (Fig. 2A). The
reasons for this reduction are the implemen-
tation of various application restrictions for
atrazine (quantitative and temporal limita-
tions and a general ban of atrazine use on
railway tracks) between 1988 and 1994, and
the subsequent adoption of substitute prod-
ucts. The reduction of the quantities applied
has had positive consequences for the
Greifensee atrazine load: whereas the total
atrazine load in the lake at the beginning
of the 1990s laid between 30 and 45 kg,
this value has dwindled to today’s 5–10 kg
(Fig. 2B). This is a significant reduction,
although surprisingly the level of atrazine
(atrazine load in Fig. 2A) detected in the
Greifensee varies greatly from year to year
during or shortly after the application period
(May till June). Thus, in 1999, when already
more than 90% of agricultural enterprises
were participating in the PEP and the ap-
plied atrazine volume had fallen by more
than 60%, there was more atrazine entering
the Greifensee than in 1994 shortly after the
implementation of the ecological measures.
In order to evaluate the success of the eco-
logical measures, not only the quantities
applied, but also those influencing factors
which have an effect on the pesticide trans-
port from the field to the water, need to be
known.
No Detectable Reduction of Pesticide Losses The quantity of pesticide entering the water
body is chiefly dependant on the point in
time and the quantity and intensity of pre-
cipitation events following the application of
the pesticide. The corollary being that up to
half of an annual load can be washed by the
rain into a water body in a matter of days or
weeks following a pesticide application. Al-
together, the proportion of pesticide which
is transported from the land to the water
body amounts to only a few per cent of the
total applied.
Figure 3 shows no variation in the atrazine
losses to the Greifensee after introduction of
the PEP. Instead, a strong correlation be-
tween rain intensity and atrazine runoff is
evident. The largest rainfall was registered in
1999: in this year 3.4% of the applied atra-
zine was transported into the Greifensee.
On the other hand, in low rain years, the
transported atrazine quantities range be-
tween 0.5 and 1.9%.
Wat
er b
ody
load
/ A
pp
lied
qua
ntity
(%)
4
3
2
1
00.5 1.0 1.5 2.0 2.5
Water runoff in the major stream to the Greifensee (m3/s)
0.0
19982003
2002
1990 2000
1997 1994
19912001
1999
Fig. 3: The percentage of the atrazine transportedfrom the field to the water body during or shortly afterthe application period increases with increased waterrunoff during rain events. Data and correlation uncer-tainties are not shown.
19 EAWAG news 59
[1] Schweizerische Gesellschaft für chemische Industrie
SGCI (2004): Schweiz und Fürstentum Liechtenstein
Pflanzenbehandlungsmittel-Markt-Statistik
1988–2003.
[2] Müller S.R., Berg M., Ulrich M.M., Schwarzenbach
R.P. (1997): Atrazine and its primary metabolites in
Swiss lakes: Input characteristics and long-term
behavior in the watercolumn. Environmental Sciences
and Technology 31, 2104–2113.
[3] Leu C., Singer H.P., Stamm C., Müller S.R., Schwar-
zenbach R.P. (2004): Simultaneous assessment of
sources, processes, and factors influencing herbicide
losses to surface waters in a small agricultural catch-
ment. Environmental Sciences and Technology 38,
3827–3834.
[4] Leu C., Singer H.P., Stamm C., Müller S.R., Schwar-
zenbach R.P. (2004): Variability of herbicide losses
from 13 fields to surface water within a small catch-
ment after a controlled herbicide application. Environ-
mental Sciences and Technology 38, 3835–3841.
[5] Stamm C., Singer H., Szerencsits E., Zgraggen K.,
Flury C. (2004): Standort und Herbizideinsatz aus
Sicht des Gewässerschutzes. Agrarforschung 11,
446–451.
[6] Gerecke A.C., Schärer M., Singer H.P., Müller S.R.,
Schwarzenbach R.P., Sagesser M., Ochsenbein U.,
Popow G. (2002): Sources of pesticides in surface
waters in Switzerland: pesticide load through waste
water treatment plants – current situation and reduc-
tion potential. Chemosphere 48, 307–315.
A similar picture appears for other maize
herbicides. Results from a field study which
investigated the maize herbicides atrazine,
dimethenamid, metolachlor, and sulco-
trione, in smaller sections of the Greifensee
catchment area, show that these sub-
stances have a similar transport behavior
[3]. Rain washes them away very quickly
so that the herbicides dissolved in the rain
water could not attach the soil matrix. The
rapid transport of pesticides during a heavy
rain event is due mainly to surface runoff
and rapid flow into subsurface drainage sys-
tems.
Further Measures for Success Further studies in the catchment area of the
Greifensee show that waterlogged sites with
direct connection to a water body have a
great potential for pesticide loss [4]. Also
from an agronomical point of view, these
sites are not ideal as farmland [5]. On such
sites of high risk for pesticide losses, pesti-
cide usage should be avoided. This should
be possible in practice since high pesticide
losses often appear as local “hot spots”,
and Swiss agriculture is structured in rela-
tively small-scale units. Pesticide-free areas
could be allocated in part as ecological
compensation areas required to obtain
subsidies through direct payment. A clear
identification of high-risk sites is a great
challenge for future pesticide research.
During disposal of pesticide residues, and
during cleaning of the field sprayers, pesti-
cides can be transported directly via the
sewerage system or indirectly through the
sewage plant into the water bodies. In the
Greifensee, these point sources for sub-
stances which are used exclusively in agri-
culture make up between 15 and 20% of
the total pesticide load [6]. A solution lies in
appropriate training in order to learn the cor-
rect handling of pesticides, which can be
regulated with licenses. Any person who
uses pesticides professionally must be in
possession of the appropriate license. In
addition, the spraying machines must be
regularly inspected. Since most spraying
machines are quite old, financial assistance
in acquiring modern sprayers brings addi-
tional improvement potential. Freshwater
tanks on modern sprayers make it possible,
for instance, to clean the machines directly
in the field.
ConclusionA causal relationship between the imple-
mented policy measures for improving the
environmental impact situation in agricul-
ture and for reducing the pesticide load in
water bodies is difficult to establish, and
necessitates many simplifications and re-
strictions. On the one hand, the complexity
and temporal behavior of environmental
systems per se appear not to be compatible
with the timeframes of political decision-
making. Politics demand simple, clear and
rapid answers, whereas research attempts
to bring about an understanding of complex
and chaotic systems, which normally re-
quires resource-consuming and expensive
investigations extending over a long time
period. For this reason, it would have been
important to have already started the corre-
sponding assessment programme prior to
Heinz Singer is a chemist in thegroup Water and Agriculture inthe Department of Environmen-tal Chemistry. He is currentlyinvestigating the fate of pesti-cides in the environment and isdeveloping methods for detect-ing organic trace elements.
Pollution analysis – taking water samples in Greifensee.
the introduction of the ecological measures
in 1993.
Nevertheless, despite data uncertainty and
knowledge gaps, certain concrete trends
are identifiable: The measures for limiting
pesticide usage have led to a visible if only
partial success. On the contrary, the trans-
port limiting measures have been less suc-
cessful and must be reconsidered for the
future.
EAWAG news 59 20
Pesticides: Risks to Lakes and Streams?
Pesticide residues are most undesirable in surface waters. Byapplying a global quality criterion of 0.1 µg/l, the Swiss WaterProtection Ordinance to date does not discriminate between thedifferent effects of the over 400 registered active substances. To improve this situation, Eawag proposes an effect-based riskassessment approach for individual pesticides and pesticide mix-tures.
For many years, Swiss surface waters have
been contaminated by a wide variety of
pesticides [1]. Due to their toxic function in
curbing damaging pests and weeds, pesti-
cides are also hazardous to flora, fauna and
microorganisms in lakes and streams.
Water pollution, resulting from agricultural
use of pesticides, usually follows a season-
al pattern. Pesticide concentrations are par-
ticularly high if applied to fields during or
shortly after rain events: values of up to a
few µg/l have then been measured in
streams and medium-sized rivers [2]. The
quantity of pesticides reaching water bodies
from farmland is dependent on the physico-
chemical properties of the substances,
topography of the landscape and soil char-
acteristics [2]. Some 20 – mostly herbicides
– of the more than 400 active pesticides
registered in Switzerland are found regu-
larly in surface waters (Tab. 1).
Some of these substances are extremely
toxic, others less toxic. For effective water
protection, a realistic assessment of the
risks presented by individual pesticides or
pesticide mixtures is therefore essential.
Such a risk assessment requires the inte-
gration of as much ecotoxicity data as pos-
sible, currently lacking in most evaluation
methods. Eawag is therefore developing an
effect-based risk assessment system in col-
laboration with the Federal Office of Envi-
ronment, Forest and Landscape (FOEFL).
Based on the available ecotoxicity data, this
system allocates an individual water quality
criterion to each pesticide expressing the
specific pesticide concentration, which
should not be exceeded in surface waters
in order not to endanger aquatic organisms.
A second step involves the integration of
the effect-based quality criteria in the risk
assessment.
Traditional Risk AssessmentThe risk presented by a pesticide is usually
calculated by means of Formula 1 (see Box
“Formulas”) [3]. If the risk factor is below 1,
the probability for aquatic organisms to be
damaged by the pesticide is relatively low.
If the factor is above 1, the damage proba-
bility is high. The quality criterion of 0.1 µg/l,
established by the Swiss Water Protection
Ordinance, allows identification of polluted
water bodies, but not performance of a risk
evaluation, since this quality criterion has
been arbitrarily defined without any consid-
eration of the varying effects of the different
pesticides.
In other countries, effect-based quality cri-
teria are used for risk assessment [4–7].
Application as Product
Herbicide 2,4-D, atrazine, dicamba, dimefuron, dimethenamid, diuron, ethofumesat, isopro-turon, linuron, MCPA, mecoprop, metamitron, metazachlor, metolachlor, napro-mide, propachlor, simazine, tebutam, terbuthryn, terbuthylazine, and triclopyr
Insecticide Diazinon and primicarb
Fungicide Metalaxyl, oxadixyl and penconazole
Tab. 1: Some 20 pesticides are regularly detected in Swiss water bodies.
Risk quotient of a pesticide = RQ =pesticide concentration in water body
=MEC
quality criterion quality criterion
Risk quotient of an individual pesticide = RQi =MEC
HC5-95%
Risk quotient of a pesticide mixture = RQm = �n
i=1RQi = �
n
i=1
MECi = MEC1+ … + … +
MECn
HC5-95%i HC5-95%1 HC5-95%n
RQ = risk quotient, MEC = see Glossary, i = individual substance, m = mixture, n = number of pesticides in mixture
FormulasFormula 1
Formula 2
Formula 3
21 EAWAG news 59
A = relationship of reference to pesticide 1B = relationship of reference to pesticide 2
log NOEC
log EC50
Ref
eren
ce
Pes
ticid
e 1
Pes
ticid
e 2
AB
Ref
eren
ce
log NOEC
Ref
eren
ce
Pes
ticid
e 1
Pes
ticid
e 2
AB
Sp
ecie
s af
fect
ed (%
)
Stage 1100
00 1 2 3 4 5
75
50
25
Sp
ecie
s af
fect
ed (%
)
Stage 2100
0–2 –1 0 1 2 3
75
50
25
Sp
ecie
s af
fect
ed (%
)
Stage 3100
0–2 –1 0 1 2 3
75
50
25
HC5-95%-Reference HC5-95%-
Pesticide 1 HC5-95%-Pesticide 2
Fig. 1: The three stages of the recently developed cal-culation method for more consistent HC5-95% values.See text for further explanations.
However, these assessment criteria also
have weak points. The currently most wide-
spread, effect-based quality criterion is the
PNEC value (see Glossary). When calculat-
ing the PNEC value, all ecotoxicity test data
(EC50 and NOEC values, see Glossary) are
taken into consideration. However, as the
PNEC value is ultimately based on the low-
est EC50 or NOEC value, criticism to that
effect that the PNEC is reliant on a single
data point is justified. In addition, the PNEC
value is provided with arbitrarily selected
security factors (see Glossary).
For some years, the hazardous concentra-
tion HC (see Glossary) has been used as an
effect-based quality criterion in risk assess-
ment [8]. Calculation of the HC is dependent
on the statistical assessment of NOEC data
available in the literature (see Box “Haz-
ardous Concentration”). However, one of
the difficulties in calculating reliable HC val-
ues is the required input of at least 10 NOEC
values from chronic toxicity tests – a require-
ment not currently met by most pesticides.
A New Method to CalculateSound, Effect-based QualityCriteriaDespite these drawbacks, the HC is cur-
rently the most reliable parameter we have.
Our project therefore focused on establish-
ing a method allowing calculation of the HC
value, even with few or no NOEC data avail-
able. Specifically, we have chosen the HC5-
95% value (see Box “Hazardous Concen-
tration”) as the effect-based quality
criterion.
Our method comprises three stages (Fig. 1):
1. SSD curves based on EC50 (see Glossary
and Box “Hazardous Concentration”) were
established for all pesticides in the mixture
as well as for a reference pesticide. The
more abundant EC50 data were chosen in-
stead of the NOEC values. As a reference, a
pesticide is chosen on which 8–10 long-
term and short-term tests had been carried
out ensuring sufficient NOEC and EC50
data. Subsequently, the so-called “toxicity
ratio” is calculated between the individual
SSD-EC50 pesticide curves and the SSD-
EC50 curve of the reference pesticide.
2. A second SSD curve provided with confi-
dence range is established for the reference
substance – based this time on the NOEC
values available in the literature.
3. The SSD-NOEC curves of the other sub-
stances, including the confidence range, are
plotted on the basis of the SSD-NOEC curve
of the reference substance. This is possible
by using the toxicity ratio calculated at the
start. Finally, the HC5-95% for each sub-
stance was derived from the new SSD-
NOEC curves.
However, our new method can be used in
practice only if the following two hypothe-
ses are verified:� Pesticides with similar action modes show
parallel SSD-EC50 and SSD-NOEC curves.
The “Hazardous Concentration” HCHC values are calculated from so-called “Species SensitivityDistribution” curves (SSD curves) [8] in which the distributionof the NOEC data is logarithmically plotted against the per-centage of the species affected. In the ideal case, the NOECdata are distributed log-normal, resulting in an S-shapedcurve in cumulative plotting of SSD. In practice, HC5 valueshave become established. They designate the pesticide con-centration at which 5% of the total number of species areendangered or 95% of all the species are protected. The SSDcurves may also be provided with a confidence interval. Thesmaller the confidence interval, the better is the quantity and quality of the available ecotoxicity data. This confidenceinterval allows calculation of the HC5-95% value. It express-es with a 95% probability the pesticide concentration atwhich 5% of the species are endangered and 95% are pro-tected. The HC5-95% value is always lower than the HC5 val-ue – the smaller the confidence interval, the more the twovalues converge [9].
log NOECHC5-95% HC5
log NOECHC5-95% HC5
Sp
ecie
s af
fect
ed (%
)
0
5
Sp
ecie
s af
fect
ed (%
)
0
5
EAWAG news 59 22
� The “toxicity ratio” between the SSD-
EC50 and the SSD-NOEC curves is con-
stant.
Since studies on the SSD curves are fairly
recent, it is unclear whether these hypothe-
ses are correct. A comparison of the SSD-
NOEC curves, derived by this method with
the few NOEC data available from literature,
indicates that our assumptions are accept-
able.
The HC5-95% values will have to be regular-
ly updated if additional effect data become
available. Availability of more data increases
HC significance.
Our RecommendationsIn future, our method will allow calculation of
consistent HC5-95% values. We therefore
recommend the following measures:� The global quality criterion of 0.1 µg/l,
established by the Swiss Water Protection
Ordinance, should be replaced by individual
HC5-95% values.� For risk assessment of individual sub-
stances, the individual HC5-95% pesticide
values should be used in Formula 2 as ef-
fect-based quality criteria (see Box “Formu-
las”).� The HC5-95% values can also be used in
risk assessment of pesticide mixtures, pro-
vided the mixtures contain pesticides with
similar action modes. This is where the
concept of concentration additivity can be
applied. According to this theory, concen-
trations of substances with similar effect
mechanisms can be weighted and added
according to their toxicity [10], and their
risks then calculated by using Formula 3
(see Box “Formulas”).
Example: Risk Assessment of5 HerbicidesThe risk of a herbicide mix in the small river
Aa near Mönchaltorf, Canton of Zurich was
assessed with the method described above.
The mixture comprised 5 herbicides, each
an inhibitor of photosynthesis affecting the
photosystem II. Although their sites of ac-
tion are not identical [11], these herbicides
follow the concept of concentration additiv-
ity [Chèvre et al., soon to be published].
Atrazine was chosen as the reference herbi-
cide. To calculate the SSD curves, only tox-
icity data from tests on aquatic primary pro-
ducers (algae and aquatic flora) were used,
since they are the most sensitive to this type
of pollutant. Figure 2A classifies the 5 herbi-
cides according to their SSD-EC50 curves.
Diuron is the most toxic herbicide, followed
by isoproturon, terbuthylazine, atrazine, and
simazine. In Figure 2B, the SSD-EC50
curves are transposed to the SSD-NOEC
Sp
ecie
s af
fect
ed (%
)
100
80
60
40
20
0–1 0 1 2 3 4 5
log EC50
A
Sp
ecie
s af
fect
ed (%
)
100
80
60
40
20
0–2 –1 1 2 3 4 5
log NOEC
B
0
AtrazineTerbuthylazineSimazineIsoproturonDiuron
AtrazineTerbuthylazineSimazineIsoproturonDiuron
Fig. 2: Individual HC5-95% values for the five pesti-cides in a pesticide mixture were calculated with thenew method. SSD curves were plotted from EC50data (A), allowing the corresponding SSD-NOECcurves to be derived (B).
A B
Ris
k fa
ctor
2
1.5
1
0.5
0Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Ris
k fa
ctor
2
1.5
1
0.5
0Jan Feb Mar Apr May Jun Jul Aug Sep Oct
Cumulative risk of the five pesticides Risk from isoproturon Risk from atrazine Risk from diuron
Fig. 3: Risk assessment of the five pesticides in a pesticide mixture.
Nathalie Chèvre, EnvironmentalEngineer and Ecotoxicologist,now heads the group AppliedEcotoxicology in the Depart-ment of Environmental Toxicol-ogy. A further research focus isthe modular stepwise procedurefor ecotoxicological assessmentof running waters.
Co-author: Beate Escher
23 EAWAG news 59
position in May (Fig. 3A). Secondly, some
herbicides occur not only during their appli-
cation period, but have also been regularly
detected throughout the year. These sub-
stances reveal a constant baseline load as
in the case of our study on diuron, which is
not only used as a herbicide, but also as a
preservative in paints. Diuron appears to be
continuously washed off from house sur-
faces and subsequently transported into
lakes and streams (Fig. 3B). In our research
region, diuron is not used as a herbicide, but
mainly applied in viticulture. Nevertheless,
this should not be underestimated, since it
largely contributes to the total risk, along
with the baseline risks of the other herbi-
cides.
Our results indicate the importance of inte-
grated herbicide management.
OutlookThe recommended method is currently used
to calculate new quality criteria for the most
commonly detected herbicides in water
(triazine, phenylurea, chloroacetanilide), as
well as for a specific group of insecticides,
the organophosphates, of which diazinon is
[1] Chèvre N. (2003): Risikobeurteilung von Pestiziden in Schweizer Oberflächengewässern. Gas Wasser Abwasser 12,
906–917.
[2] Leu C. (2003): Sources, processes and factors determining the losses of atrazine, dimethenamid and metolachlor to
surface waters: A simultaneous assessment in six agricultural catchments. Dissertation, ETH Zürich, 89 S.
[3] European Commission (2003): Technical guidance document on risk assessment. TGD Part II, Institute for Health and
Consumer Protection, European Chemicals Bureau, European Commission, Ispra, Italy, 329 p.
[4] Roussel P. (1999): Système d’évaluation de la qualité des cours d’eau. Rapport de présentation SEQ-Eau. Agence de
l’eau Loire-Bretagne, 59 p.
[5] Länderarbeitsgemeinschaft Wasser, LAWA (1998): Zielvorgaben zum Schutz oberirdischer Binnengewässer. LAWA,
Berlin, Band III, 12 S.
[6] Ministère de l’environnement (2001): Critères de qualité de l’eau de surface au Québec. Direction du suivi de l’environ-
nement, Ministère de l’environnement, Québec, 430 p.
[7] Crommentuijn T., Sijm D., de Bruijn J., van den Hoop M., van Leeuwen K., van de Plassche E. (2000): Maximum
permissible and negligible concentrations for some organic substances and pesticides. Journal of Environmental
Management 58, 297–312.
[8] Posthuma L., Suter G.W.I., Traas T.P. (2002): Species sensitivity distributions in ecotoxicology. Boca Raton, Lewis
Publishers, 587 p.
[9] Aldenberg T., Slob W. (1993): Confidence limits of hazardous concentrations based on logistically distributed NOEC
toxicity data. Ecotoxicology and Environmental Safety 25, 48–63.
[10] Backhaus T., Altenburger R., Arrhenius Å., Blanck H., Faust M., Finizio A., Gramatica P., Grote M., Junghans M., Meyer
W., Pavan M., Porsbring T., Scholze M., Todeschini R., Vighi M., Walter H., Grimme L.H. (2003): The BEAM-project:
prediction and assessment of mixture toxicites in the aquatic environment. Continental Shelf Research 23, 1757–1769.
[11] Peterson D.E., Thompson, C.R., Regehr, D.L., Al-Khatib, K. (2001): Herbicide mode of action. Kansas State University,
24 p. http://www.oznet.ksu.edu/library/crpsl2/samplers/C715.asp
Risk Parameter GlossaryMEC = Measured Environment Concentra-tion – indicates the pollutant concentrationactually detected in the water body.
EC50 = Effect Concentration 50% – usuallydetermined by laboratory testing for acutetoxicity. It expresses the pollutant concen-tration at which 50% of the exposed or-ganisms show the tested effect. Mortalityis generally used as the indicator.
NOEC = No-Observed Effect Concentration– usually determined by laboratory testingfor chronic toxicity. It expresses the pollu-tant concentration at which no effect isdetectable. Usually reproduction or growthis used as the indicator.
PNEC = Predicted No-Effect Concentration– calculated from EC50 and NOEC data. Itexpresses the pollutant concentration atwhich no effect is expected in the field.The PNEC is based on the lowest EC50and/or NOEC values and is also providedwith a security factor. The lower this factor,the greater the availability of chronic toxic-ity data (NOEC data) and number of testedtrophic levels (levels in the nutrition pyra-mid). The security factor includes theuncertainty obtained when the limitedamount of laboratory toxicity data are ex-trapolated to natural conditions.
HC = Hazardous Concentration, derivedfrom SSD curves, indicates the concentra-tion corresponding to a given level of envi-ronmental protection (see Box “HazardousConcentration”).
SSD Curves = Species Sensitivity Distribu-tion Curves – represent the percentage ofspecies affected as a function of the pollu-tant concentration (log NOEC) (see Box“Hazardous Concentration”).
curves as described in stage 3 of our
method.
The risk of damage of this herbicide mixture
to aquatic ecosystems in spring (March to
May) sometimes clearly exceeds 1 (Fig. 3A).
If we consider the risks posed by the individ-
ual herbicides in the mixture, two phenom-
ena can be observed: Firstly, the impact
risks for the herbicides in water can also be
superimposed if they are applied at different
times. This is the case for isoproturon and
atrazine used in March to April and May to
June respectively, showing a risk of super-
detected regularly in the water. Further pes-
ticide groups will soon follow.
In the context of standardization, it is of
utmost importance to establish clear rules
for pesticide sampling. Definition of these
rules and selection of sampling sites are the
subject of a parallel project. The results of
both projects could be useful as reference
material for revision of the Swiss Water Pro-
tection Ordinance.
EAWAG news 59 24
Changing demands on the cultivated and natural landscape lead to land use conflicts between agricultural production, work andrecreation purposes, and environmental protection. An economicland use model also integrating environmental factors enables usto assess the developments in agrarian structures and agriculturalland use and to deduce their impacts on the environment.
Agricultural land use is associated with both
negative and positive effects. The positive
effects are primarily the productive use and
the cultivation of the landscape. Among the
most serious negative effects is the input
of nitrogen, phosphorus, and pesticides into
surface and ground waters, resulting from
losses during use. In addition, these inputs
are increased by land use activities which
are unsuitable to their location.
Where Is Swiss AgricultureHeading to? The scale of the positive and negative ef-
fects of land use depends on two intercon-
nected factors: the choice of land use activ-
ities by landowners and the allocation of
land use activities to a particular location.
The decisions of farmers are determined
by production techniques and other busi-
ness management considerations, such as
prices, direct payments and technical reg-
ulations. On top of these considerations,
location choice is influenced by the avail-
ability of suitable land. If a farm has little
suitable land at its disposal, there is a risk
that some land will be used for unsuitable
purposes. And furthermore, the agricultural
basic conditions are constantly changing,
requiring farm management to adapt appro-
priately.
In order to assess structural developments
and future land use, we have developed a
so-called sectoral land use model as part of
the project “Sustainable land use and
forestry production in Greifensee Watershed
Area”. Our model allows us to predict the
development of the agricultural sector at a
regional level, in our case for the Greifensee
region. The model shows, on the one hand,
how agricultural enterprises react econom-
ically to changing agricultural basic con-
ditions. On the other hand, the model was
extended to a series of environmental pa-
rameters [1]. It is therefore possible to inves-
tigate the effects of land use changes on the
environment. In this article, we focus on the
question of whether expected land use is
suitable to the specific location and what
effects land use activities will have on the
pesticide load in the environment.
Land Use Model and ScenariosUsing the land use model, the total income
of the agricultural sector in the Greifensee
region was maximized. In addition, it de-
rived optimal land use and animal hus-
bandry for the farms and the region as a
whole. Agricultural production is therefore
modeled so as to reflect the real farms in
the Greifensee region. For the model cal-
culations, a series of assumptions has to be
made, the most important of which concern:� the available production factors like land
and manpower,� the production functions,� the labor costs of family-owned man-
power,� the structural changes: the total number of
enterprises should not decrease by more
than 2.6% per annum, corresponding to the
structural change seen over recent years.
The agricultural structural development was
calculated for a reference scenario and two
future scenarios (see box). 2011 was chosen
as the time horizon. Table 1 summarizes the
key figures for the two future scenarios.
Scenario Swiss Way 2011If in the Swiss Way 2011 scenario full labor
costs are assumed, today’s structures shift
in the direction of more extensive farming.
Livestock is relatively heavily reduced,
which is primarily the result of a lower milk
production. With the assumed milk price of
55 centimes per litre, only 80% of the cur-
rent milk volume would be produced. In
comparison to dairy animals, the reduction
of livestock in labor-extensive animal hus-
bandry is less pronounced. Suckler cow
husbandry would, on the other hand, in-
crease considerably. As a result of the
changes in animal husbandry, the feed crop
farming would decrease. Ecological com-
pensation areas would increase greatly,
mainly fallow land on arable land and exten-
sively used meadows. The increase in ex-
Scenarios and Basic ConditionsReference Scenario 2000: In this scenario the year 2000 was simulated, meaning that all the pre-vailing basic conditions (political and market environment) which the farmer was confrontedwith in 2000 were used. Due to the census of agricultural holdings and the geo-referenced landuse database [2], there are no gaps in the knowledge of factors which are important for themodel. We are therefore in the position to validate the land use model, and to identify the effectsof the model’s assumptions.
Scenario Swiss Way 2011: In this scenario, no further liberalization steps are implemented otherthan decided in the Agricultural Policy 2007. The greatest changes are the lifting of the produc-tion quotas and the liberalization of the cheese market. So for milk in 2011, a price of 55 cen-times is assumed, while the remaining produce prices sink by 20–30% compared to 2000. Forcosts there is no clear trend and the direct payments system is maintained in its current form.
Scenario Opening 2011: In comparison to the scenario Swiss Way 2011, this scenario assumesthat the market price support is entirely abolished, and border protection with the EU is elimi-nated. Produce prices re-orient towards the European prices and lie at 35–75% below the initiallevel in the year 2000. The decline in costs is primarily felt in the concentrated feedstuffs sectorin an European environment.
Promoting LocationSuitable Land Use
25 EAWAG news 59
Swiss Way 2011 Opening 2011
Exclusive labor costs
Inclusive labor costs
Exclusive labor costs
Inclusive labor costs
Sector income 98% 72% 83% 65%
Income/labor unit 64% 104% 54% 94%
Arable land/ASA 110% 76% 106% 40%
Open arable land/ASA 79% 89% 76% 42%
Fodder cultivation/ASA 192% 59% 189% 47%
Livestock (LU) 147% 76% 149% 83%
LU/Fodder cultivation area 121% 75% 121% 72%
Milk production 335% 80% 338% 95%
Ecological compensationareas/ASA
127% 237% 146% 287%
Tab. 1: Agricultural structural development in the future scenarios Swiss Way 2011 and Opening 2011 (relative toReference Scenario 2000). Labor unit = one fully employed person, ASA = agricultural surface area, LU = livestockunit (e.g. 1 cow = 1.0 LU or 1 bull = 0.6 LU).
tensively used meadows is related to the
lower labor requirements, high direct pay-
ments, and the lower fodder quality require-
ments of suckler cows.
Clearly, the level of the assumed labor costs
has a strong influence on the agricultural
structures. Should these costs be disre-
garded, then the decrease of product prices
in animal husbandry is compensated by
higher stock levels and more intensive pro-
duction. In this case, the entire sector
income stabilizes at today’s level, whereby
the income per labor unit falls significantly.
If one includes labor costs and the change-
over to (labor-)extensive systems, the op-
posite picture appears: despite reductions
in sector incomes, agricultural enterprises
achieve today’s income levels per labor
unit.
Scenario Opening 2011Basically, the effects described for the sce-
nario Swiss Way 2011 also apply for the
scenario Opening 2011 (Tab. 1). The differ-
ences between the two scenarios are due to
the different assumptions regarding prices,
costs and direct payments. In particular,
falling prices for cash crops have consider-
able impacts in this scenario. As a result,
arable farming is reduced significantly. As in
the scenario Swiss Way 2011, lower product
prices have an effect on incomes. Taking full
labor costs into account, income per labor
unit in the scenario Opening 2011 is 10%
lower than in the scenario Swiss Way 2011.
Is Today’s Land Use Optimizedfor Location?Along with the general structural develop-
ments in agriculture, we were interested to
know to what extent land use would change
and whether land would be cultivated in a
location suitable way. In Figure 1A, the land
use distribution for the year 2000 is shown
as derived from a supervised classification
of air photographs [2]. Figure 1B shows the
optimal land use in Reference Scenario
2000. Clearly, there is unfavorably located
arable farming in the current situation: ap-
proximately 20% of land which is suitable
for extensive perennial grassland only is
used for arable farming, and only 44% of
land which is classed as unrestricted crop
rotation area is used for arable farming
(Fig. 1A). On the contrary, the Reference
Scenario 2000 chooses more arable farming
on the yield rich locations and uses the land
predestined for perennial grassland exclu-
sively for roughage production (Fig. 1B).
This raises the question why agricultural
enterprises do not use their land for location
suitable activities. An important reason is
ownership and leasehold. In the current sit-
uation, there is a shortage of suitable arable
land for single operators, who are conse-
quently obliged to use unsuitable land. In
the model, on the other hand, individual
single-operator ownership and leasehold
are not represented [1]. The model farms
are therefore much more flexible in the com-
position of their properties, so that in Ref-
erence Scenario 2000 exclusively crop rota-
tion land is used for arable farming.
Is Future Land Use Optimizedfor Location?The land use model does not answer this
question in an unambiguous way:� On the one hand, the share of open arable
land in the two future scenarios declines
(Tab. 1). This induces a corresponding de-
crease in the shortage of crop rotation land
in the future scenarios, so that it would be
theoretically possible to re-establish arable
farming in suitable locations.� On the other hand, in the future scenar-
ios the land area for cereals, potatoes and
sugar beet declines, while fallow land area
on arable land increases. As a conse-
Extensiveperennial grassland
Intensiveperennial grassland
Fodder emphasizedcrop rotation
Cereals emphasizedcrop rotation
Unrestrictedcrop rotation
Scenario Opening 2011
0 70605040302010
(%)
Scenario Swiss Way 2011
0 70605040302010
(%)
Reference Scenario 2000
0 70605040302010
(%)
Reality 2000
0 70605040302010
(%)
A B C D
CerealsFallow land onarable landMaize
Misc. cashcrops
Fig.1: Arable farming by land use suitability in reality [2] (A), in the Reference Scenario 2000 (B), and in the two future scenarios Swiss Way 2011 (C) and Opening 2011 (D). See box for the description of the scenarios. Miscellaneous cash crops: potatoe, sugar beet, rapeseed.
Christian Flury, agriculturaleconomist at the Institute ofAgricultural Economics at ETHZurich, is the project leader ofthe integrated research project“Greifensee” and, as a partner inthe firm Flury & Giuliani GmbH,offers consulting services in the
fields of agriculture and regional economics.
EAWAG news 59 26
quence, there is an increase in the planting
of maize, a crop which can also be planted
in less suitable locations. Very likely, a cer-
tain share of grassland will continue to be
used for arable farming, which is not com-
patible with location suitability (Fig. 1C + D).
Environmental ImpactsWith the expected animal husbandry and
land use, the impacts on the environment
also change. Table 2 shows how nitrogen
and phosphorus losses change, as does
the share of cultivated land in pesticide risk
locations. While the nitrogen losses remain
more or less proportional to the arable farm-
ing area, phosphorus losses fall with the
livestock sizes. On the other hand, the share
of pesticide risk locations used for arable
farming clearly increases with full labor
costs in the scenario Swiss Way 2011: more
than 10% of the risk locations are used for
arable farming, instead of around 3–6% as
in the other scenarios. This is due to the fact
that more land will be used with a lower
degree of suitability, and that these loca-
tions are often pesticide risk locations [3].
Requirements for LocationSuitable Land UseFrom our results, it is clear that an extensi-
fication of agriculture is to be expected in
the future: decreasing animal stocks, lower
intensity in roughage production, and ex-
pansion of ecological compensation areas.
This trend will be further emphasized by
structural changes. Evaluations of the cur-
rent structures in the Greifensee region
show that large farms hold fewer animals
per land unit than smaller farms [4]. The
increasing flexibility due to the structural
change makes it possible for farm managers
to limit the inappropriate use of land for
arable farming, so that in comparison to to-
day’s use, a more suitable farming of the
arable land can be expected. It can also be
expected that the negative effects of agri-
culture on the environment will decline.
Independent of this long-term development,
location suitable use of land can be promot-
ed by the design of the direct payments sys-
tem, i.e. the requirements for the right to
receive direct payments. Under the current
system, with the exception of the Ecological
Quality Regulation [5], no criteria for location
suitability are considered: the hazard poten-
tial for water and the revaluation potential
for biodiversity, which varies in response to
location factors, are not taken into account.
Further results obtained with the land use
model show that the network of environ-
mental compensation areas can be signifi-
cantly improved by linking the environmen-
tal direct payments to location selectivity [6].
Likewise, the cultivation of crops with high
plant protection demands can be limited on
pesticide risk locations with incentives or
bans. Since there are relatively few pesticide
risk locations in the Greifensee region, a ban
on cultivation of arable crops with high plant
protection demands on these risk locations
will have only limited effects [6]. However, in
particular areas or on individual farms the
structural effects of a ban can be consid-
erably greater. The extent of the effect de-
pends on the shortage of crop rotation
land and its classification as risk locations.
Furthermore, it must be taken into account
that pesticide losses do not only depend on
location (un)suitable land use [3]. Along with
a restriction of pesticide use in high risk lo-
cations, other measures which are designed
to reduce the application of pesticides and
their losses should also be applied.
The investigations in the Greifensee project
highlight that the location characteristics
of land should be included in any future
agricultural policy. At the same time, it has
become clear that the existing state of
understanding – in particular regarding the
question of how agricultural activities, loca-
tion characteristics of land, and the resulting
environmental impacts, are interrelated –
is insufficient. These gaps in knowledge
must be closed quickly.
[1] Zgraggen K., Flury C., Gotsch N., Rieder P. (2004):
Entwicklung der Landwirtschaft in der Region Greifen-
see. Agrarforschung 11, 434–439.
[2] Schüpbach B., Szerencsits E. (2000): Landnutzungs-
layer der Greifenseeprojekt internen GIS-Datenbank.
Zürich-Reckenholz, Eidgenössische Forschungs-
anstalt für Agrarökologie und Landbau (FAL).
[3] Stamm C., Singer H., Szerencsits E., Zgraggen K.,
Flury C. (2004): Standortgerechtigkeit des Herbizid-
einsatzes aus Sicht des Gewässerschutzes. Agrar-
forschung 11, 446–451.
[4] Zgraggen K. (2005): Zgraggen K. (2005): Ökonomische
Evaluation der ökologischen Massnahmen in der
Schweizer Landwirtschaft, Dissertation, ETH Zürich.
[5] Ecology Quality Regulation:
http://www.admin.ch/ch/d/sr/c910_14.html
[6] Zgraggen K., Flury C., Gotsch N., Rieder P. (2004):
Gestaltung der Landnutzung in der Region Greifensee.
Agrarforschung 11, 470–477.
Swiss Way 2011 Opening 2011
Exclusive labor costs
Inclusive labor costs
Exclusive labor costs
Inclusive labor costs
N losses � � � �P losses � � � �Proportion of arable farmingon pesticide risk locations
� � � �Tab. 2: Changes in substance losses in the Greifensee watershed area in the future scenarios Swiss Way 2011 andOpening 2011 (relative to Reference Scenario 2000). The risk locations for pesticide loss were identified with thehelp of a simple indicator [3].
Kurt Zgraggen, agriculturaleconomist at the Institute ofAgricultural Economics at ETHZurich, developed the sectoralland use model for the integrat-ed research project “Greifensee– sustainable land use andforestry production in the Grei-
fensee Watershed Area” as part of his PhD thesis.
27 EAWAG news 59
National Strategy for AgriculturalNitrogen Reduction
In Switzerland, around 50% of ecologically
relevant nitrogen emissions come from agri-
culture [1]. The reduction of these emis-
sions constitutes a challenge for politics, re-
search and agriculture. However, this is not
straightforward. Nitrogen compounds are
an integrated part of natural material cycles
and to some extent can be transported over
great distances. Moreover, the majority of
nitrogen emissions originate from nonpoint
sources. As a result, the generator cannot
be easily identified, which makes the imple-
mentation of incentives and efficiency ori-
ented instruments in environmental policy
more difficult [2, 3].
Nitrogen Strategy in SwitzerlandTo protect humans and the environment
against harmful and annoying effects of
nitrogen compounds, targets have been
established in national legislation and inter-
national agreements which aim at achieving
precautionary emission reductions that are
technically feasible and economically viable.
In addition, the project group Nitrogen Bal-
ance Switzerland [1] developed on behalf
of the federal government strategies for a
stepwise minimization of environmentally
relevant nitrogen emissions. These are also
reflected in the environmental targets of
the current agricultural policy (AP 2007) [4,
5]. Amongst others, the project group elab-
orated on the basis of scientific investiga-
tions, the medium-term objective for overall
reductions in total emissions of environ-
mentally relevant nitrogen compounds into
air and water. For Swiss agriculture, this
would require emission reductions of about
14 kt nitrogen until 1998, and 22 kt nitrogen
per year until 2002 [1]. The Federal Parlia-
ment postponed the fulfillment deadline
within the frame of AP 2007 to the year 2005
[4, 5].
Furthermore, the project group Nitrogen
Balance Switzerland formulated ecologi-
cally-based long-term goals for the emis-
sions of nitrous oxides and ammonia, as
well as for nitrogen runoff from agriculture
[1]. In addition, it proposed that the total
nitrogen losses to the environment must be
halved in the long run, i.e. the annual fluxes
must be reduced from 96 kt nitrogen in 1994
to the ecological target of 48 kt nitrogen [4].
In contrast, no concrete targets exist for
nitrous oxide emissions. These should,
however, be taken into account in connec-
tion with the Kyoto Protocol obligations for
reducing total Swiss greenhouse gas emis-
sions.
Methods for AssessingNitrogen LossesIn conjunction with the project group Nitro-
gen Balance Switzerland, the Institute of
Agricultural Economics (IAW) of the Swiss
Federal Institute of Technology (ETH) Zurich
developed a method [6] to calculate the
nitrogen loss potential and nitrogen losses
to the environment from agriculture for dif-
ferent farm types. The approach is based on
a random sampling of farms, taken from the
totality of the balance sheet declarations of
the Swiss Farmers Union (SBV) and the Ser-
vice romande de la vulgarisation de l’agri-
culture (SRVA), the agricultural information
service for the French speaking part of
Switzerland. These provide data about pur-
chases of seeds and marketed fertilizers,
sales of plant and animal products, as well
as changes of livestock. For the estimation
of nitrogen quantities used in Swiss agri-
culture and the related loss potential, key
figures were assessed for the different farm
types and extrapolated to the entire agricul-
tural area of Switzerland. Complementary,
using statistical data provided by the SBV, a
global calculation was provided, in which
Swiss agriculture is regarded as only one
enterprise.
Nitrogen Loss: Down and Up AgainRecent calculations with these two methods
show an initial decline of the nitrogen loss
potential after 1993/4 and an increase since
1997/98 [5, 7]. This result is also supported
by other assessments. The OSPAR method
[8], for instance, reveals the same develop-
ment in the annual nitrogen balance. The
excess of nitrogen inputs clearly declined
between 1990 and 1997, and is currently ris-
ing again [5].
Figure 1 shows the development through
time of the nitrogen loss potential calculat-
ed with the IAW method, which accounts for
stable, storage, application and utilization
losses. It becomes apparent that the esti-
mated nitrogen loss potential is slightly
higher when taking into account new scien-
tific knowledge and the progress in agri-
cultural production [9], than with the old co-
efficients from 1994. This might particularly
be due to changes in animal husbandry and
a lower plant availability of farm manure.
For the reduction of environmentally harmful nitrogen emissionsfrom agriculture, the project group Nitrogen Balance Switzerlandformulated environmental targets that have also found considera-tion in current agricultural policy. Recent calculations show thatthe intermediate goal for 2005 cannot be achieved. Responsiblefor this is, amongst others, the lack of sufficient and targetedeconomic incentives. These could be created through a system ofsteering levies on nitrogen fertilizer and a spatially differentiatedland use tax.
EAWAG news 59 28
(in kt N/year) 1990 1994 1998 2002 2005 Ecologicaltarget d)
Nitrous oxide b) 4.2 4.1 3.9 3.8
Ammonia 54.4 51.3 49.7 47.8
Nitrogen oxides 3.3 3.1 2.9 2.8
Nitrate 44.9 41.7 39.2 38.5
Environmentally relevant N-loads 106.8 100.1 95.7 93.0
Changes since 1994 –4.6% –7.1%
Agro-environment stage targets c) –14.6% –22.9% –22.9% –50%
Table 1: Environmentally related nitrogen losses and agro-environmental targets a).
a) Own calculation as described in the text.b) Without indirect emissions.c) According to the project group Nitrogen Balance Switzerland and Agricultural Policy 2007, respectively [1,5]. d) Long-term ecological target [4].
Unfortunately, problems emerged with the
extrapolation of the sample data that limit
the interpretability of the results for the indi-
vidual farm types and the partition of the
loss potential to the various nitrogen forms.
These problems trace back to the fact that
the calculation method was originally de-
signed for the validation of calculations with
an agricultural economic model, rather than
as a monitoring tool. In addition, the conti-
nuity and representability of the data is neg-
atively affected by fluctuations in the set of
bookkeeping farms with SBV and SRVA, as
well as structural shifts between farm types.
This particularly affects the composition of
the nitrogen loss potential and the calcula-
tion of the environmentally relevant nitrogen
losses. For this reason, no reliable state-
ments can be made about the level and de-
velopment of nitrogen losses to the environ-
ment for 2002 with the IAW method.
Alternatives are however available. One op-
tion is the use of the nitrogen loss potential
without breaking it down to individual loss-
es. According to the project group Nitrogen
Balance, the corresponding stage target
for 2002 would correspond to a reduction
of 28 kt nitrogen per annum compared to
1994. As illustrated in Figure 1, this target is
still far from being achieved.
A second option is the calculation of envi-
ronmentally relevant nitrogen loads using
the IULIA method [10] and the national
greenhouse inventory, provided annually
according to international guidelines [11].
Table 1 shows the corresponding values for
selected years. Since these values are
slightly higher than those used to date, the
effectiveness of agricultural policy meas-
ures can only be evaluated with regard to
proportional changes compared to 1994.
These support the assumption [5] that the
agro-ecological stage target might not be
achieved even in the year 2005.
ExplanationReasons for this development, which is un-
desirable from an ecological point of view,
are [5, 7]:� the re-increase of mineral nitrogen fertil-
izer use,� the higher nitrogen requirement of the cul-
tivated plants,� the increase in the number of free-move-
ment stables,� changes in the feeding recommendations,� the increase in imported fodder,� the temporary storage of organically
bound nitrogen in the soil.
Moreover, the uncertainty in the calculation
of nitrogen fluxes into the environment and
the complexity and dynamics of natural
systems [10], together with technological
and economic developments may have an
effect. From an economic point of view in
particular, changes in relative prices and
restrictions on individual management op-
tions through regulations play a decisive
role in the choice of individual activities and
factor inputs as well as for the diffusion of
new production alternatives.
A Double Research NeedCorrespondingly, the requirements on re-
search double. On the one hand, we must
better understand the effects of changing
agricultural production systems on the
nitrogen balance, and, on the other hand,
integrate this knowledge into appropriate
mathematical-scientific models (including
error estimations). This creates at the same
time a basis for reliable economic analyses,
which can react very sensitively to changes
in relative prices, political framework condi-
tions and new technological possibilities. In
particular with regard to changes in relative
prices and production techniques, the real
development since 1994 has diverged from
the predictions in model calculations used
by the project group Nitrogen Balance [1, 6].
This explains at least to a certain extent
the existing gap to the policy targets for
reducing the nitrogen loss potential.
Evaluation and PolicyRecommendations from anEconomic PerspectiveIn view of this gap, the question arises about
adequate measures for reducing nitrogen
losses from Swiss agriculture. From an eco-
nomic point of view, priority must be given
kt n
itrog
en p
er a
nnum
125
120
115
110
105
1001993 1997 2001
Year
with progress in productionwithout progress in production
Fig. 1: Development of the nitrogen loss potentialaccording to the global calculation [5, 9].
29 EAWAG news 59
To increase yields, the fields are sprayed with fertilizers, a part of which enters the environment unused.
[1] Projektgruppe Stickstoffhaushalt Schweiz (1996): Strategie zur Reduktion von Stickstoffemissionen. Schriftenreihe
Umwelt Nr. 273, BUWAL/BLW, Bern.
[2] Shortle J.S., Abler D. (Eds) (2001): Environmental Policies for Agricultural Pollution Control. CABI Publishing, Walling-
ford, UK, New York, USA.
[3] Hediger W. (2003): Alternative policy measures and farmers’ participation to improve rural landscapes and water
quality: A conceptual framework. Schweiz. Zeitschrift für Volkswirtschaft und Statistik 139, 333–350.
[4] BUWAL (2003): Reduktion der Umweltrisiken von Düngern und Pflanzenschutzmitteln. Bundesamt für Umwelt, Wald
und Landschaft, Bern.
[5] BLW (2004): Agrarbericht 2004. Bundesamt für Landwirtschaft, Bern.
[6] Häfliger M., Keusch A., Lehmann B., Thomi H.-P., Wolf H.P. (1995): Stickstoffhaushalt Schweiz – Anpassungsschritte
landwirtschaftlicher Betriebe zwecks Abbau der N-Emissionen. Technischer Bericht, Institut für Agrarwirtschaft, ETH
Zürich.
[7] Werder D., Perrin P.-Y., Dubach M., Gerwig C., Hediger W., Lehmann B. (2004): Technischer Bericht über die Entwick-
lung des Stickstoff-Verlustpotenzials der Schweizer Landwirtschaft von 1994 bis 2002. Institut für Agrarwirtschaft,
ETH Zürich.
[8] OSPAR = Oslo-Paris-Commission; protection of the marine environment of theNorth-East Atlantic. www.ospar.org
[9] Reidy B., Menzi H. (2004): Ammoniakemissionen in der Schweiz: Neues Emissionsinventar 1990 und 2000 mit Hoch-
rechnungen bis 2003. Technischer Schlussbericht zuhanden BUWAL. Schweiz. Hochschule für Landwirtschaft (SHL),
Zollikofen, Bern.
[10] Schmid M., Neftel A., Fuhrer J. (2000): Lachgasemissionen aus der Schweizer Landwirtschaft. Schriftenreihe der FAL
33, Eidg. Forschungsanstalt für Agrarökologie und Landbau, Zürich-Reckenholz.
[11] Swiss Greenhouse Gas Inventory, http://www.climatereporting.ch/ghg.html
[12] Griffin R.C., Bromley D.W. (1982): Agricultural runoff as a nonpoint externality: A theoretical development. American
Journal of Agricultural Economics 64, 547–552.
[13] Schmid H. (2001): Umweltpolitische Instrumente in der Agrarpolitik: Eine ökonomische Analyse der Oberflächen- und
Grundwasserbelastung durch Phosphor und Nitrat aus dem Ackerbau. Diss. ETH Nr. 14 299, ETH Zürich.
[14] Peterson J.M., Boisvert R.N., de Gorter H. (2002): Environmental policies for a multifunctional agricultural sector in
open economies. European Review of Agricultural Economics 29, 423–443.
Werner Hediger, economist, issenior assistant and lecturer inresource and environmentaleconomics at the Institute ofAgricultural Economics at ETHZurich. His primary researchinterest is in the economics ofsustainable development and
integrated environmental policy.
EA
WA
G
to the introduction of input charges (“steer-
ing taxes”), even if they have repeatedly
been rejected with reference to other meas-
ures [1, 4].
Steering taxes are incentive-oriented eco-
nomic instruments which, in contrast to reg-
ulative legislation, enable a cost-effective
(i.e. cost-minimizing and resource-protect-
ing) attainment of environmental targets
through the correction of relative prices.
This can theoretically be achieved by levy-
ing a charge (a price) on nitrogen emissions,
and by this means creating an incentive for
the internalization of external costs [2]. Such
a policy is however complicated by the fact
that emissions originate from a wide range
of sources and cannot be easily observed.
As an alternative to charging emissions,
environmental economists therefore pro-
posed a system of taxes on all inputs that
are responsible for the generation of emis-
sions. This taxation system has the same
efficiency characteristics as emission or
effluent charges [12].
Related to the nitrogen problem, the solu-
tion requires the combination of a nationally
uniform charge on nitrogen fertilizers (min-
eral and manure, and not only on excess
manure) with a spatially differentiated land
use tax. This discriminating land use tax
makes it possible to appropriately take
into account individual location characteris-
tics and management practices [3, 13, 14].
Hence, past views regarding nitrogen taxes
must be reconsidered, and at the same time
investigated in a broader context of several
environmental problems and targets. This
implies the necessity for a reassessment
of the prior experience and understanding
with regard to the introduction of nitrogen
taxes in agro-environmental policy.
EAWAG news 59 30
Water protection is an important basis to the
economic viability of the Swiss agricultural
enterprises in respect of the proof for envi-
ronmental performance (PEP). If a farmer
breaks the rules of the Water Protection
Legislation, his direct payments could be
withheld.
Subjects such as the influence of anti-
biotics, natural and mineral fertilizers, and
pesticides to aquatic ecosystems are cur-
rent issues and cannot be brushed aside
in discussions of agriculture. It is therefore
indispensable that the risks that these sub-
stances present for the water are investigat-
ed and that from this knowledge, targeted
measures for the minimization of water
loads are developed. On the other hand,
policy-makers must integrate this knowl-
edge into the future orientation of Swiss
agricultural policy.
As a consultant for an environmentally
friendly agricultural production, one ques-
tion concerning the water protection discus-
sion lies particularly close to my heart: “How
do I say this to the farmers?”
Water protection is not the only nor the
greatest problem farmers face today. Be-
sides the impositions regulated by the envi-
ronmental legislation, operational and pro-
duction technical questions are essential
for the survival of an agriculture enterprise.
Our main task is, therefore, to pass on the
knowledge gained from research and policy
in a comprehensible form to the farmers, so
that they are convinced of the necessity of
ecological measures. My experience shows
that in agricultural consulting the following
expression is most applicable: For the
transfer of ideas, the language is more im-
portant than the dialect.
Agriculture lies in the contradictory context
between private management and public
commitment. More than 4 billion francs of
direct payments and subsidies flow annual-
ly into farming – a part of which is allocated
for ecological services.
These services must be defined, controlled
and communicated. The requirements
should be clear, unambiguous and mean-
ingful, and be equal between all cantons in
validity and application. Restrictions in en-
trepreneurial management are unwelcome
and are viewed as chicanery. Policy and
public demand consistent but not too strict
control, and expect in addition an improve-
ment of the environmental situation by
means of the applied measures, and the
production of healthy, tasty, and competitive
foodstuffs.
Swiss agriculture operates in a conflicting
area also affecting the accomplishment of
environmental protection. The balance be-
tween interventions and self responsibility
must be maintained, as well as the harmo-
nization of the intercantonal implementa-
tion, to minimize regional differences. These
are just two issues to which the environ-
mental protection authorities are confronted
in the field of agriculture.
The central point is communication at all
levels: on the political level the demands of
environmental protection need to be well-
founded, well-represented and balanced
between all stakeholders. In implementa-
tion, it is necessary to provide good expla-
nations to all those affected by the meas-
ures, to gain their acceptance. And the
public must become more aware of the eco-
logical services which have already been
achieved by the agricultural sector.
The integration of environmental protection
into industrial sectors is a central postulate
of environmental, economic and regional
policy. Agriculture has accepted the chal-
lenge and has been following this path now
for 15 years. There still remains, however,
a great need for further action.
The rural landscape in intensively used
areas is still strongly depleted, with its
streams completely destroyed or stripped
of their protective and landscape forming
riparian vegetation. The re-establishment of
a natural stream network requires agricul-
tural land and is one of the most important
future tasks.
The nitrogen targets of the 1999 agricultural
policy could not be achieved. The main rea-
son for this is the nitrogen imported in the
form of fertilizer and fodder. An optimized
management system would allow nitrogen
to be better used and thereby losses to be
reduced. This would also limit the quantities
of importable auxiliary agents. This is the
case for both Swiss agriculture as a whole
and for many individual agricultural enter-
prises.
Agro-ecological goals should be primarily
pursued by means of an economic incen-
tives system. These incentives will encroach
the borders of international regulation re-
gimes and economic acceptability.
Thus, agriculture as well as the rural areas
as a whole see a difficult future ahead. In this
context, enormous structural, economic
and social problems have to be solved
across Europe. New visions for a sustain-
able development of rural areas and agri-
culture as its vital industry are urgently re-
quired.
Andreas Zehnder, Agric. Eng.HTL, is leader of the Monitoringand Control Service of the Agri-culture Office Schaffhausen andis active as a consultant in thefields of cultivation and ecology.
Jürg Hertz, Deputy Head of theDepartement for EnvironmentProtection in Canton Thurgau.
Ueli Bundi, Acting Director ofEAWAG, is concerned withquestions of environmentalpolicy, water industry and water-course assessment.
F O R U MIn the conflicting area of agriculture and water protection
31 EAWAG news 59
[3657] Fenner K., Scheringer M., HungerbühlerK. (2004): Prediction of overall persistence andlong-range transport potential with multimediafate models: robustness and sensitivity of results.Environ. Pollut. 128, (1–2), 189–204.
[3662] Siegrist H., Rieger L., Fux C., Wehrli M.(2004): Improvement of nitrogen removal at WWTPZürich-Werdhoelzli after connection of WWTPZürich-Glatt. Water Sci. Technol. 50, (7), 35–43.
[3678] Wedekind C., Walker M., Portmann J.,Cenni B., Müller R., Binz T. (2004): MHC-linkedsusceptibility to a bacterial infection, but no MHC-linked cryptic female choice in whitefish. J. Evol.Biol. 17, (1), 11–18.
[3688] Bloesch J. (2004): Sedimentation and lakesediment formation. In: “The Lakes Handbook:Limnology and Limnetic Ecology”, P.E. O’SullivanC.S. Reynolds (Eds.). Blackwell Publishing, Ox-ford, 197–229.
[3701] Kettle H., Thompson R., Anderson N.J.,Livingstone D.M. (2004): Empirical modeling ofsummer lake surface temperatures in southwestGreenland. Limnol. Oceanogr. 49, (1), 271–282.
[3721] Truffer B., Harms S., Wächter M. (2004):Regional experiments and changing consumerbehaviour: The emergence of integrated mobilityforms. In: “Electric Vehicles – Socio-economicprospects and technological challenges”, R. Cow-an, S. Hulten (Eds.). Ashgate Publ. Ltd., Aldershot,U.K., 173–204.
[3739] Schmidt T.C., Zwank L., Elsner M., BergM., Meckenstock R.U., Haderlein S.B. (2004):Compound-specific stable isotope analysis oforganic contaminants in natural environments: acritical review of the state of the art, prospects,and future challenges. Anal. Bioanal. Chem. 378,283–300.
[3748] Escher B.I., Sigg L. (2004): Chemical spe-ciation of organics and of metals at biologicalinterphases. In: “Physicochemical Kinetics andTransport at Biointerfaces”, H.P. van Leeuwen, W.Köster (Eds.). John Wiley & Sons, Ltd., 205–269.
[3750] Stamm C., Waul C., Leu C., Gomides-Freitas L., Popow G., Singer H., Müller S. (2004):Sorption effects on herbicide losses to surfacewaters in a small catchment of the Swiss Plateau.Zeitschrift für Pflanzenkrankheiten und Pflanzen-schutz, Sonderheft XIX, 951–958.
[3751] Bühler J., Siegenthaler C., Simitivic R.,Wüest A., Zeh M. (2004): Trübeströmung im Grim-selsee. Wasser Energie Luft 96, (5/6), 129–135.
[3753] Rutishauser B.V., Pesonen M., EscherB.I., Ackermann G.E., Aerni H.R., Suter M.J.F.,
Eggen R.I.L. (2004): Comparative analysis of es-trogenic activity in sewage treatment plant efflu-ents involving three in vitro assays and chemicalanalysis of steroids. Environ. Toxicol. Chem. 23,(4), 857–864.
[3754] Frutiger A. (2004): Ecological impacts ofhydroelectric power production on the River Tici-no. Part 1: Thermal effects. Archiv für Hydrobiolo-gie 159, (1), 43–56.
[3755] Frutiger A. (2004): Ecological impacts ofhydroelectric power production on the River Tici-no. Part 2: Effects on the larval development of thedominant benthic macroinvertebrate (Allogamusauricollis, Trichoptera). Archiv für Hydrobiologie159, (1), 57–75.
[3756] Boller M. (2004): Towards sustainable ur-ban stormwater management. Water Science andTechnology: Water Supply 4, (1), 55–65.
[3758] Werlen C., Jaspers M.C.M., van der MeerJ.R. (2004): Measurement of biologically availablenaphthalene in gas and aqueous phases by use ofa Pseudomonas putida biosensor. Appl. Environ.Microbiol. 70, (1), 43–51.
[3759] Laemmli C., Werlen C., van der Meer J.R.(2004): Mutation analysis of the different tfd genesfor degradation of chloroaromatic compounds inRalstonia eutropha JMP134. Arch. Microbiol. 181,(2), 112–121.
[3763] Lienert J., Fischer M. (2004): Experimentalinbreeding reduces seed production and germina-tion independent of fragmentation of populationsof Swertia perennis. Basic Appl. Ecol. 5, (1), 43–52.
[3764] Dittrich M., Kurz P., Wehrli B. (2004): Therole of autotrophic picocyanobacteria in calciteprecipitation in an oligotrophic lake. Geomicrobiol.J. 21, (1), 45–53.
[3767] Rellstab C., Bürgi H.R., Müller R. (2004):Population regulation in coregonids: the signifi-cance of zooplankton concentration for larval mor-tality. Ann. Zool. Fenn. 41, (1), 281–290.
[3769] Wedekind C., Müller R. (2004): The exper-imental rearing of large salmonid eggs in Petridishes. Funct. Ecol. 18, (1), 138–140.
[3770] Köster W. (2004): Transport of solutesacross biological membranes: Prokaryotes. In:“Physicochemical Kinetics and Transport at Bio-interfaces”, H.P. van Leeuwen, W. Köster (Eds.).John Wiley & Sons, Ltd., 271–335.
[3771] Köster W., van Leeuwen H.P. (2004):Physicochemical kinetics and transport at thebiointerface: Setting the stage. In: “Physicochem-ical Kinetics and Transport at Biointerfaces”, H.P.
van Leeuwen, W. Köster (Eds.). John Wiley & Sons,Ltd., 1–14.
[3772] Muscheler R., Beer J., Wagner G., Laj C.,Kissel C., Raisbeck G.M., Yiou F., Kubik P.W.(2004): Changes in the carbon cycle during the lastdeglaciation as indicated by the comparison of10Be and 14C records. Earth Planet. Sci. Lett. 219,(3–4), 325–340.
[3773] Göbel A., McArdell C.S., Suter M.J.F.,Giger W. (2004): Trace determination of macrolideand sulfonamide antimicrobials, a human sulfon-amide metabolite, and trimethoprim in wastewaterusing liquid chromatography coupled to electro-spray tandem mass spectrometry. Anal. Chem. 76,(16), 4756–4764.
[3774] Freitas L.G., Gotz C.W., Ruff M., SingerH.P., Müller S.R. (2004): Quantification of the newtriketone herbicides, sulcotrione and mesotrione,and other important herbicides and metabolites, at the ng/l level in surface waters using liquid chro-matography-tandem mass spectrometry. J. Chro-matogr. A 1028, (2), 277–286.
[3776] Aerni H.R., Kobler B., Rutishauser B.V.,Wettstein F.E., Fischer R., Giger W., Hunger-bühler A., Marazuela M.D., Peter A., Schonen-berger R., Vogeli A.C., Suter M.J.F., Eggen R.I.L.(2004): Combined biological and chemical assess-ment of estrogenic activities in wastewater treat-ment plant effluents. Anal. Bioanal. Chem. 378, (3),688–696.
[3777] Eggen R.I.L., Behra R., Burkhardt-HolmP., Escher B.I., Schweigert N. (2004): Challengesin ecotoxicology. Environ. Sci. Technol. 38, (3),58A–64A.
[3778] Kubán P., Reinhard M., Müller B., HauserP.C. (2004): On-site simultaneous determination of anions and cations in drainage water using aflow injection-capillary electrophoresis systemwith contactless conductivity detection. J. Envi-ron. Monit. 6, 169–174.
[3779] Baur I., Keller P., Mavrocordatos D.,Wehrli B., Johnson C.A. (2004): Dissolution-pre-cipitation behaviour of ettringite, monosulfate, andcalcium silicate hydrate. Cem. Concr. Res. 34, (2),341–348.
[3784] Brennwald M.S., Peeters F., ImbodenD.M., Giralt S., Hofer M., Livingstone D.M.,Klump S., Strassmann K., Kipfer R. (2004):Atmospheric noble gases in lake sediment porewater as proxies for environmental change. Geo-phys. Res. Lett. 31, (4), art. no.-L04202.
These an all other EAWAG publications are available as pdf files under: http://library.eawag.ch/ris/risweb.isaSearch possible by author, title or keyword. In case of problems, please contact: [email protected]
Publications
I N B R I E F
9 December «Blyb gsund» in Dar es SalaamBrigit Obrist van Eeuwijk, Swiss Tropical Institute, BaselSeminar, EAWAG Dübendorf, 11:00–12:00
13 January Policy Principles and Implementation Guidelines for Public-Private Partnership inWater Supply and Sanitation: Improving Performance through Transparency andParticipationDieter Rothenberger, SECO; François Münger, SDCSeminar, EAWAG Dübendorf, 11:00–12:00
20 January Entwicklung von sozialen Techniken für die Verbreitung von SODISHansi Mosler, EAWAGSeminar, EAWAG Dübendorf, 11:00–12:00
27 January From SODIS to Household Water Treatment and Safe StorageMartin Wegelin, EAWAGSeminar, EAWAG Dübendorf, 11:00–12:00
3 February The Challenge of Fluoride Removal in Drinking WaterAnnette Johnson and Kim Müller, EAWAGSeminar, EAWAG Dübendorf, 11:00–12:00
10 February Simplified Sewerage: An Option for Low- and Middle-Income CountriesDuncan Mara, University of Leeds UK Seminar, EAWAG Dübendorf, 11:00–12:00
PersonnelJukka Jokela
is head of the De-
partment of Limnol-
ogy and Professor
for aquatic ecology
at ETH Zurich since
1 June 2005. He is particularly inter-
ested in evolutionary ecology.
Tracking Down Whitefish Decline in Lake BrienzIn the project “Changes in the Ecosystem of Lake Brienz”, EAWAG
jointly with other partners aim at determining the reasons for the mas-
sive collapse (approx. 90%) of whitefish yields in 1999. Preliminary
results from the seven subprojects were presented at the symposium
“Lake Brienz – Between Hydroelectric Power Use and Nutrient
Reduction” at the University of Berne on 23 September. The subpro-
jects study for instance the effects of the power station in the catch-
ment of Lake Brienz as well as the input of nutrients and suspended
particles to the lake. The study revealed, inter alia, a far smaller but
seasonally different input of suspended particles than observed pri-
or to construction of the power plant. In addition, the water pollution
control measures, which led to a marked nutrient decrease in Lake
Brienz and significant decline in algae production, limited the num-
ber of Daphnia (water fleas) available as fish food. On completion of
the project in summer of 2006, the different pieces of the subproject
puzzle will be assembled to obtain an overview and provide an ob-
jective assessment of the conflicting questions.
Multi-level Groundwater Flows near RiversEawag researchers and specialists of the Canton of Thurgau revealed
the existence of multi-level groundwater flows of varying origins
below and alongside the river Thur. In simple terms: The deeper
the water flow, the longer it has remained in the underground. This
is important for drinking water catchment, as the legal provisions pre-
scribe that water must remain in the underground for at least ten days
before it can be tapped to prevent contamination of drinking water.
The situation at the Thur is typical for many sites where drinking wa-
ter is conveyed from gravel-sandy valley soils. However, the ten-day
flow time cannot be observed in all catchment areas. During flood
events, this situation is further aggravated due to shorter flow paths
and increased infiltration. Even if rivers are given more space by flood
protection and revitalization measures, they could move closer to the
drinking water catchment areas. Eawag researchers therefore sug-
gest a concept of new measuring and simulation methods to obtain
differentiated solutions to the respective problems.
U. O
chse
nbei
n, G
BL
EA
WA
G
Juliane Hollender
joined the Eawag on
1 September 2005.
The chemist heads
the new Department
of Environmental
Chemistry created by the merged
departments of Water and Agriculture
and Chemical Pollutants.
Agenda
Further information: www.eawag.ch/research_e/apec >Brienzersee
and www.eawag.ch/events/brienzersee